Astrodynamics Technical Committee

AIAA Houston Section Astrodynamics technical committee

The American Institute of Aeronautics and Astronautics (AIAA)
Technical committee Chair: Dr. Albert Allen Jackson IV

Upcoming event (Lunch & Learn at NASA/JSC):

Date: Friday, January 27, 2017
Time: 11:30 AM – 1:00 PM
Place: NASA/JSC Gilruth Center Lone Star Room
Subject: Reproducing an Apollo Applications Program Single-Launch Human Venus Flyby Trajectory
Speaker: Daniel R. Adamo, Astrodynamics Consultant
Here is a link to the publicity flyer (PDF). Here is a link to EventBrite web page.

Proposed new feature in work July 27, 2016 and December 27, 2016:

The Adamo Archive in Astrodynamics

[Update, January 7, 2017] This AIAA copy of this archive is now stored in its more permanent location (URL): http://www.aiaahouston.org/adamo_astrodynamics/. This new link is also found by surfing to our Section web page, then using menu choices Technical Activities/Daniel R. Adamo Astrodynamics. This AIAA copy of the archive is a big project (thanks very much to all who made it possible and all who worked on it!) of this technical committee (TC, astrodynamics in this case) in our Section, but the new location (URL) is more permanent. This TC web page has existed for a long time thanks to its current Chair, Dr. Albert Allen Jackson IV, but TCs come and go in our Section, so we chose a more permanent location for this AIAA copy of this archive. This AIAA copy of this archive will no longer be kept here on this TC web page.  Please search this TC web page for Snoopy or the Red Baron to find a related news article. [End update of January 7, 2017] 

Dan Adamo (Daniel R. Adamo) is a longtime member of our NASA/JSC community and an expert in astrodynamics. As of July 27, 2016, when we are starting this public archive of some of his work, he is retired, living in Oregon, and he is a popular Distinguished Lecturer (DL) of AIAA. The DL manual lists his 3 presentations, and he has completed a 4th presentation to be added to that list:

  • Interplanetary Cruising With Earth-To-Mars Transit Examples
  • Aquarius, A Reusable Water-Based Interplanetary Human Spaceflight Transport
  • Questioning The Surface Of Mars As The 21st Century’s Ultimate Pioneering Destination In Space
  • Depot locations supporting Human SpaceFlight (HSF)

Mr. Adamo has been emailing his Astrodynamics Technical Integration Group (ATIG) for years. We suggested publishing those outgoing ATIG email notes here, along with the email attachments (PDF documents, GIFs [image files]), etc. He said yes to our request, so we present below a bulleted list. The first is from 2008, and the latest is from 2016 as we start this project in the fall of 2016. Here is a link to the Dan Adamo ATIG email signature. Mr. Adamo encourages anyone interested in receiving his ATIG email notes to email him at adamod [at] earthlink [dot] net. These ATIG files (such as GIF image files of trajectory plots and PDF files) are stored in an AIAA Houston Section Horizons (newsletter) directory, not the default WordPress or Bluehost directory, so these files are archived on an AIAA Houston Section server owned by our hosting service BlueHost.

  • ATIG_084__2016_12_01 [December 1, 2016] Cassini’s Final Titan Flybys
    ATIG Members- This week, NASA’s robotic explorer Cassini entered the ring-grazing phase of its planned 13 years in Saturn orbit. Flybys of Saturn’s largest moon Titan have played a primary role in managing Cassini’s tour of Saturn, its rings, and its moons. Only one of these flybys, the 126th, remains. When it’s performed next April, Cassini will be in its grand finalé phase and on a path to disposal in Saturn’s atmosphere 15 September 2017. Details regarding Cassini’s endgame, and how Titan flybys enable it, are provided in the attached PDF file. Happy holidays to all as we boreals approach 2016’s winter solstice! -Dan
    [Link to PDF, 10 pages, 544 KB, FinalTitanFlybysR0.pdf]
    Here is a link to the original ATIG #84 .eml (email) file. 
  • ATIG_083__2016_11_17 [November 17, 2016] A Survey of Interplanetary HSF Transport Mars Orbit Geometries
    ATIG Members- Last month, I had the pleasure of conversing with members of NASA’s Evolvable Mars Campaign (EMC), an architecture effort that recently studied what HSF might explore during an extended stay on Phobos, the inner moon of Mars. Although funding limitations precluded a similar EMC study of a HSF mission to that other moon of Mars, Deimos, I was more concerned to learn the Phobos study intentionally assumed the Mars approach and departure trajectories, together with the nearly equatorial orbit of Phobos, are coplanar. The EMC’s assumption inspired me to survey planar geometries associated with arrivals at and departures from Mars for Earth roundtrips during a 15-year synodic cycle. This amounts to studying eight successive Mars missions to even begin comprehending geometric variations in these arrivals and departures. The attached draft paper documents my survey’s results. Comments are welcome, as always. Before closing, let me recognize that a lot of ATIG members are located in Greater Houston. My itinerary is still preliminary, but let me give you a heads-up that AIAA’s Houston Section will be hosting me for multiple presentations at local venues. Current planning has me at Gilruth Center for a Lunch & Learn on Friday, January 27 and at the UH Main Campus on Saturday, January 28. I hope to see many of you during my first trip to Houston since moving to Oregon 4 years ago. -Dan
    [Link to PDF file, 13 pages, 771 KB, Asymptote-DefinedPlanesR0.pdf]
    Here is a link to the original ATIG #83 .eml (email) file.
  • ATIG_082__2016_09_12 [September 12, 2016] OSIRIS-REx Trajectory Planning
    ATIG Members- The robotic sample return mission OSIRIS-REx (Origins Spectral Interpretation Resource Identification Security Regolith Explorer) launched as planned on 8 September 2016 at 23:05 UT. This mission’s destination is (101955) Bennu (1999 RQ36), a carbonaceous near-Earth object (NEO) about 500 m in diameter. Reports and details about the mission are available at http://www.asteroidmission.org/. Due to its on time launch, planned trajectory data for OSIRIS-REx posted 31 August 2016 to JPL’s Horizons ephemeris server at http://ssd.jpl.nasa.gov/?horizons are reasonably valid for visualization purposes. The attached 5-page PDF file reflects these data and contains inertial geocentric, heliocentric, and Bennu-centered trajectory plots. Note the fifth plot in the attachment illustrating Bennu-centered motion at OSIRIS=REx arrival is very preliminary and subject to change as the asteroid’s gravity field and spin state are determined in this time frame. However, the basic arrival strategy appears to involve surveying Bennu from above its terminator with a brief dayside equatorial flyby at close range circa 24 November 2018. Bennu-centered positions for the fifth plot were sampled from Horizons at hourly intervals. -Dan
    [Link for PDF attachment (5 pages, 436 KB)]
    Here is a link to the original ATIG #82 .eml (email) file.
  • ATIG_081__2016_09_06 [September 6, 2016] Orthographic Trajectory Plots
    ATIG Members- I‘ve been sharing the subject plots with some of you since ATIG was formed in 2003. Over the years, I’ve received a few inquiries regarding the method behind these plots. The most recent of these inquiries motivated the attached explanation. Please respond with any corrections, omissions, or questions you’d like addressed. -Dan
    [Link: OrthoTrajPlottingR0.pdf, 360 KB, 3 pages.]
    Here is a link to the original ATIG #81 .eml (email) file.
  • ATIG_080__2016_07_28 [July 28, 2016] “Aquarius” Proposal
    ATIG Members- Those of you on ATIG distribution in March 2014 will recall receiving a draft paper titled “Aquarius, A Reusable Water-Based Interplanetary Human Spaceflight Transport”. Since then, the paper has morphed into an American Institute of Aeronautics and Astronautics (AIAA) distinguished lecture I present at venues across the U.S. As of today, 28 July 2016, the paper has been published as a peer-reviewed article in Acta Astronautica Vol. 128 (2016) pp. 160-179. Until 16 September 2016, you may download a “final version” of the published article at http://authors.elsevier.com/a/1TSDrLWHFg814 free of charge. [That links to this PDF: 1-s2.0-S0094576516300868-main.pdf. (2.8 MB, 20 pages)] Many ATIG members contributed helpful feedback on Aquarius, and I believe at least one of you served as a peer reviewer for Acta. This feedback has been very helpful to the subject proposal’s maturation and is greatly appreciated. In the final version, a parenthetical sentence appears at the end of many figure captions. The “web version” to which readers are referred in this sentence is one and the same with the “final version” available for download. Enjoy! -Dan
    Here is a link to the original ATIG #80 email file.
  • ATIG_079__2016_07_08 [July 8, 2016] Juno’s Journey
    ATIG Members- Attached (PDF, 304 KB) are Sun and Jupiter-centered plots of Juno’s trajectory extending from shortly after launch on 2011 Aug 5 through this week’s Jupiter orbit insertion (JOI) burn and ending on 2016 Aug 26.0 UT. Juno trajectory data are imported from JPL’s Horizons ephemeris server at http://ssd.jpl.nasa.gov/?horizons as posted on 12 May 2016 and should effectively be “as flown” at the plots’ scales. A retrograde burn is scheduled on 19 Oct 2016 to reduce Juno’s orbit period about Jupiter to 14 days. -Dan
    Here is a link to the original ATIG #79 email file.
  • ATIG_078__2016_06_24 [June 24, 2016] Earth Pseudo-Moons
    ATIG Members- This month, I’ve received multiple inquiries concerning dynamics associated with near-Earth object (469219) 2016 HO3. These are explained and visualized in the attached (PDF, 798 KB, 11 pages) white paper, together with those of another more remote object undergoing similar geocentric motion. Your questions and comments on this paper are welcome. -Dan
    Here is a link to the original ATIG #78 email file.
  • ATIG_077__2016_06_09 [June 9, 2016] Trajectory Reproduction Of A Proposed Apollo Era Piloted Venus Flyby
    ATIG Members- With the subject proposal originating circa 1967 at the facility now known as NASA-JSC, it’s fitting I was introduced to alternate space history author Jerry Brennan by JSC colleagues in November 2015. Since then, I’ve collaborated with Jerry to reproduce an example trajectory in accord with the Apollo Era proposal, helping substantiate the technical basis for his latest story titled Island of Clouds. The attached paper documents this Venus flyby trajectory reproduction in detail. Your questions and comments on this paper are welcome. -Dan
    [Link: 14 pages, 389 KB, PDF]
    Here is a link to the original ATIG #77 email file.
  • ATIG_076__2016_05_29 [May 29, 2016] Embarking on a 2016-17 Stint as Oregon Eclipse Docent
    ATIG Members- With less than 15 months to go before the Moon’s umbra sweeps across my part of Oregon, I inaugurated an educational outreach campaign on safely watching the 2017 August 21 solar eclipse in a May 24 visit to nearby Amity Middle School  Presentation charts from the Amity visit are attached, and I wish clear skies to anyone planning some “umbra time” in 2017. Happy Memorial Day! -Dan
    [Link: 13 pages, 840 KB]
    Here is a link to the original ATIG #76 email file.
  • ATIG_075__2016_05_18 [May 18, 2016] Re: ISS Nears a 6-Figure Orbit Count
    ATIG Members- With Orbit 100,000 entered in ISS logbooks earlier this week, I’ve added a Section 4 to the white paper you received last September. The new section begins on p. 5 in the attached PDF file and documents a best-estimate reconstruction of the actual milestone. This is certainly an event worth celebrating! -Dan
    [Link to PDF of May 18, 2016: 6 pages, 340 KB]
    From: Daniel Adamo
    Date: Wed, 16 Sep 2015 16:43:06 -0700
    Conversation: ISS Nears A 6-Figure Orbit Count 
    Subject
    : ISS Nears A 6-Figure Orbit Count
    ATIG Members
    In a low-Earth orbit context, orbit count is typically defined as a tally of northbound equator crossings or ascending nodes. A satellite logging more than 16 ascending nodes per day is about to enter earth’s atmosphere and end its orbit lifetime. Since its first element Zarya was launched in 1998, ISS has been logging over 15 ascending nodes per day. Only through a dedicated international planning and logistics effort has it been possible to maintain ISS orbit lifetime for 17 years such that it’s about to reach an orbit count of 100,000. Robotic spacecraft have attained 6-figure orbit counts before, but probably not in less than 20 years after launch. The attached white paper attempts to predict when the 100,000-orbit milestone will occur for ISS. All URLs in the attachment should be clickable if your PDF reader supports this behavior, but you may have to manually copy and paste URLs into your web browser if they occupy multiple lines in the PDF. As always, comments are welcome. -Dan
    Here is a link to the original ATIG #75 email file.
  • ATIG_074__2016_05_07 [May 7, 2016] Solar Eclipses in GEO
    ATIG Members- From my readings into space-based solar power (SBSP) proposals, I’ve encountered some wishful thinking about 24/7/365 sunlight in geosynchronous Earth orbit (GEO). So, I decided to research solar eclipses in GEO to quantify how they’d affect SBSP generation from that venue. In the process, I’ve come up with an infrastructure deployment strategy reducing cumulative time spent in GEO solar eclipses. This research is captured in the attached PDF file. As always, your feedback on this work is invited and appreciated. Those of you on ATIG distribution as of September 16, 2015 will recall an upload on that date with subject “ISS Nears A 6-Figure Orbit Count”. As predicted at that time, ISS will tally Orbit Number 100,000 just before midnight CDT on May 15, 2016. I intend to reconstruct this event after it’s history and will issue an “as-flown” revision to the September 16 upload later in May. -Dan
    [Link tp PDF: 536 KB, 9 pages]
    Here is a link to the original ATIG #74 email file.
  • ATIG_073__2016_03_14 [March 14, 2016] Apollo 15 Trans-Earth Trajectory Reconstruction
    ATIG Members- Since February 24, I’ve had the pleasure of working with an ESA researcher on documenting Apollo 15’s trajectory during its homeward journey from the Moon in 1971. As many veterans from the Apollo Era can attest, as-flown trajectory data for crewed lunar missions are hard to come by, particularly with temporally dense content. There are horror stories I’ve been told about retaining magnetic tapes with Apollo tracking data on them until weekly justification forms had to filed, the NASA data archivist gave up the paper chase, and the tapes were released by default to be overwritten. I’m reasonably assured Federal record-keeping has more integrity these days, but don’t ever let someone trash your flight data! The attached white paper documents the Apollo 15 trajectory reconstruction, its motivation, and a rare opportunity to spot-check some reconstructed positions with archived data whose pedigree is reasonably authoritative. As always, your feedback on this research is welcome. -Dan
    [Link to PDF: 8.2 MB, 7 pages]
    Here is a link to the original ATIG #73 email file.
  • ATIG_072__2016_01_16 [January 16, 2016] “Cassini” Heads for Higher Inclinations at Saturn
    ATIG Members- Happy 2016! During most of 2015, NASA’s Cassini spacecraft orbited Saturn very near the planet’s equatorial plane. This enabled close flybys of moons other than Saturn’s largest (Titan), including Enceladus with its ice geysers (ref. http://planetaria.ca/2015/02/cassini-data-indicates-enceladus-ocean-similar-to-soda-lakes-on-earth/). Cassini began departing Saturn’s equator to progressively greater inclinations the evening of 2016 Jan 15 (U.S. local time) with its 115th targeted Titan flyby (T-115) since achieving orbit about Saturn in 2004. The effects of T-115 on Cassini’s Saturn-centered motion are illustrated in the attached trajectory plot. The gravity assist associated with T-115 increased Cassini’s orbit inclination with respect to Saturn’s equatorial plane from 1.3 deg to 4.1 deg. It also increased Cassini’s orbit period from 12.85 days to 15.95 days. The orbit period of Titan is 15.95 days, so Cassini is, for the time being, in a 1 : 1 resonance with this moon and its power to further evolve the spacecraft’s orbit. For details on where Cassini is headed next, see http://saturn.jpl.nasa.gov/mission/saturntourdates/. -Dan
    [Link to PDF: 1 page, 100 KB]
    Here is a link to the original ATIG #72 email file.
  • ATIG_071__2015_11_29 [November 29 2015] Hayabusa-2’s Journey to Ryugu 
    ATIG Members- At 4:22 UT on 3 Dec 2014, Japan launched Hayabusa-2, its second ion-propelled spacecraft designed to visit a near-Earth asteroid (NEA). The destination for this mission is a volatile-rich NEA recently named Ryugu (dubbed 1999 JU3 when discovered) and estimated to be 920 m in diameter. For the last year, Hayabusa-2 has been in a slightly more elliptical orbit than Earth’s about the Sun. This orbit also has a 1 : 1 resonance with Earth’s, facilitating an Earth flyby and gravity assist into Ryugu’s orbit plane on 3 Dec 2015. Thereafter, Hayabusa-2 will slowly close with Ryugu from behind and sunward of it, arriving in mid-2018. This week’s Earth flyby trajectory, together with a series of yearly heliocentric trajectory plots, are attached to illustrate Hayabusa-2’s outbound journey. Trajectory data are based on a 28 Nov 2015 update to JPL’s Horizons ephemeris server at http://ssd.jpl.nasa.gov/?horizons. After about 18 months surveying and sampling Ryugu, Hayabusa-2 is to begin a one-year journey back to Earth in late 2019. The return date, when samples are to be delivered by an atmospheric entry capsule, will be very close to 3 Dec 2020. The attached heliocentric plots illustrate why major Hayabusa-2 mission events involving Earth tend to fall on December 3. This point in Earth’s orbit is only about 240,000 km (roughly 60% of the Moon’s geocentric distance) from Ryugu’s ecliptic plane descending node. On 29 Dec 2020, Ryugu will be very close to this node and only 9 million km from Earth. That geometry makes Hayabusa-2’s return propulsion requirements easy to satisfy, even if Ryugu departure date is postponed. As this may be 2015’s last ATIG upload, I’ll take the opportunity to wish you happy holidays and a joyous 2016! -Dan
    [Links: Five PDF files, each one page, each less than 120 KB. (1) Hayabusa2ega.pdf (2) Hayabusa2helio14-15.pdf (3) Hayabusa2helio15-16.pdf (4) Hayabusa2helio16-17.pdf (5) Hayabusa2helio17-18.pdf
    Here is a link to the original ATIG #71 email file.
  • ATIG_070__2015_10_29 [October 29, 2015] Cislunar Artifact WT1190F
    ATIG Members- Attached are some trajectory plots and predictions I’ve made for WT1190F, currently thought to be debris from an unidentified lunar mission. News reports are concentrating on its predicted entry Friday, 13 November 2015 at 06:20 UT. The acronym formed by alphabetic components of “WT1190F” is also attracting humorous remarks. But I’m thinking WT1190F’s lasting legacy is to human space flight architects and mission planners working on visits to NASA’s “Proving Ground” in cislunar space. We need to minimize abandoned artifacts and debris sent through the Proving Ground because a hypervelocity hit to spacecraft or habitats days from Earth return is potentially more hazardous to crew survival than are hits aboard ISS. What debris we do send into cislunar space needs to be catalogued and tracked as diligently as are those ISS threats. And what we cannot reliably track due to its small size and great distance must be shielded against with added spacecraft/habitat mass. Comments on the attachment and these remarks are welcome. -Dan
    [Link to PDF file, 322 KB, 5 pages, WT1190F#29trajR0.pdf. To make the link work properly, I changed # to [numbersign]…]
    Here is a link to the original ATIG #70 email file.
  • ATIG_069__2015_10_22 [October 22, 2015] NASA’s Journey to Mars Document
    ATIG Members- Attached is another of my seemingly ceaseless essays commenting on our culture’s fixation with sending humans to Mars. It’s a great dream, even if its rationale is elusive, but some of the strategies and associated rhetoric being used to implement it are turning the dream into a nightmare for me. How about you? There’s one poorly supported tidbit appearing at the top of p. 6 in my essay on which I’d particularly like feedback to confirm or refute it. What’s become of NASA’s open competition to develop “advanced” boosters with liquid or solid propellant for the evolved SLS? If this competition has been indefinitely frozen, SLS may never evolve beyond capability to deliver 105 t mass to low Earth orbit. That shortfall could be a game-changer, even in the cislunar “Proving Ground”. In that event, my chief consolation would be the Saturn 5 retaining its status as “the most powerful [and capable] rocket ever built”. -Dan
    [Link to PDF, 142 KB, 7 pages, JTMcommentaryR0.pdf]
    Here is a link to the original ATIG #69 email file.
  • ATIG_068__2015_09_16 [September 16, 2015] ISS Nears A 6-Figure Orbit Count
    ATIG Members- In a low-Earth orbit context, orbit count is typically defined as a tally of northbound equator crossings or ascending nodes. A satellite logging more than 16 ascending nodes per day is about to enter earth’s atmosphere and end its orbit lifetime. Since its first element Zarya was launched in 1998, ISS has been logging over 15 ascending nodes per day. Only through a dedicated international planning and logistics effort has it been possible to maintain ISS orbit lifetime for 17 years such that it’s about to reach an orbit count of 100,000. Robotic spacecraft have attained 6-figure orbit counts before, but probably not in less than 20 years after launch. The attached white paper attempts to predict when the 100,000-orbit milestone will occur for ISS. All URLs in the attachment should be clickable if your PDF reader supports this behavior, but you may have to manually copy and paste URLs into your web browser if they occupy multiple lines in the PDF. As always, comments are welcome. -Dan
    [Link to the PDF document, 176 KB, 4 pages, ISSorb100kR0.pdf]
    Here is a link to the original ATIG #68 email file.
  • ATIG_067__2015_06_30 [June 30, 2015] Space News Editorial on FBC
    ATIG Members- Several in this group have asked to be notified when the op-ed draft sent your way on May 21 was published. It was posted earlier on June 30 at http://spacenews.com/op-ed-humans-to-mars-in-20-years-a-faster-better-cheaper-sequel/. As always, I appreciate any feedback on these words, but mainly editorial changes have been applied since the May 21 draft. To those who inspired these changes, please accept my sincere thanks! -Dan
    From: Daniel Adamo <adamod@earthlink.net>
    Date: Thu, 21 May 2015 17:27:24 -0700
    Conversation: An Op-Ed On Our Headlong Rush To Mars
    Subject: An Op-Ed On Our Headlong Rush To Mars
    ATIG Members- In an attempt to put my essay on the AM II report in a broader context, I’m drafting an op-ed intended for publication in Space News (see the attached PDF file). It’s arguable that risks associated with Apollo Moon landings were justified by national prestige during the Cold War. I see nothing approaching this level of justification for taking even bigger risks in sending humans to Mars using an “affordable”, minimalist architecture. From bitter experience in the Shuttle Program, I’ve learned to appreciate affordability not just in monetary terms. There’s a human cost to affordability too. I welcome feedback on this op-ed. In particular, let me know if you’ve found any “unobtainium” on Mars only humans can extract. -Dan
    From: Daniel Adamo <adamod@earthlink.net>
    Date: Tue, 14 Apr 2015 12:04:40 -0700
    Conversation: An Essay Commenting On The AM II Report
    Subject: An Essay Commenting On The AM II Report
    ATIG Members- I became aware of the second in a series of Affording Mars workshops (AM II) when its proceedings and findings were reviewed at the Future In-Space Operations (FISO) telecon of 4 February 2015. You can download charts and an audio transcript of this telecon at http://spirit.as.utexas.edu/%7Efiso/telecon/Thronson-Cassady_2-4-15/.
    The FISO presentation refers its audience to an AM II report. Since I took issue with much of the presentation’s material, I felt compelled to review the report in detail. My commentary from this review is attached in the subject essay. Your feedback on the essay is invited, and you are welcome to share it with stakeholders and other interested parties in your network. Please note I’ve already sent the essay to all the report’s editors whose email addresses I could find. I invite feedback from all essay readers, and I hope this dialog helps foster future workshops with greater integrity and ability to build a broader, more informed consensus on the why/how/when of human Mars exploration. -Dan PS: if your organization would like to hear more about the “why” or the “how” of human Mars exploration, I’d be willing to personally share my research on either subject in a one-hour presentation. All I ask in compensation is reimbursed travel expenses.
    Here is a link to the original ATIG #67 email file.
  • ATIG_066__2015_06_22 [June 22, 2015] Re: “Dawn” Achieves Ceres Orbit
    ATIG Members- A first update to the March 30 Dawn ephemeris (referenced in the plot accompanying April 4’s ATIG upload below) was posted to JPL’s Horizons server circa June 18. This reflects initial as-flown trajectory reconstruction of arrival in the RC3 orbit (13,600 km in altitude) and a spiral down to the Survey orbit (4400 km in altitude), completed on June 3. These milestones are plotted with respect to Ceres, as viewed from its equatorial plane, in the attached PDF. On June 22, Dawn is completing her sixth southbound data collection pass over the dayside of Ceres in the Survey orbit. After the eighth Survey orbit is complete late in June, Dawn is to begin lowering her altitude once again. -Dan
    [Link to PDF, 122 KB, 1 page, CeresAppR3.pdf]
    From: Daniel Adamo <adamod@earthlink.net>
    Date: Sat, 04 Apr 2015 12:11:40 -0700
    Conversation: “Dawn” Achieves Ceres Orbit
    Subject: Re: “Dawn” Achieves Ceres Orbit
    ATIG Members- Updating Dawn’s approach to (1) Ceres, the attached plot of Ceres-centered motion has SEP thrusting modeled into the mid-April time frame. This plot is viewed from Ceres’ equatorial plane in a direction looking “up” in the plot sent March 8. From the updated trajectory, SEP thrusting to achieve Dawn approach over Ceres’ north rotational pole is evident. Planned SEP thrusting in late April (not modeled in this plot’s ephemeris) will achieve a circular “RC3” orbit at 13,500 km altitude on April 23. You can read more about Dawn’s Ceres approach at http://dawnblog.jpl.nasa.gov/?p=2437. -Dan
    From: Daniel Adamo <adamod@earthlink.net>
    Date: Sun, 08 Mar 2015 21:45:51 -0700
    Conversation: “Dawn” Achieves Ceres Orbit
    Subject: “Dawn” Achieves Ceres Orbit
    ATIG Members- About the time most of us in the U.S. were arising on Friday morning, March 6, the Dawn spacecraft was achieving orbit about dwarf planet asteroid (1) Ceres. Because Dawn uses solar electric propulsion (SEP), its thrust duty cycles are highly flexible and equally uncertain because of the low accelerations exerted. The attached plot of Dawn’s Ceres-centered motion depicts orbit capture, but SEP thrusting doesn’t appear to be modeled much after March in the associated ephemeris posted March 6 to http://ssd.jpl.nasa.gov/?horizons. According to http://dawnblog.jpl.nasa.gov/2015/03/06/dawn-journal-march-6/, Dawn should be in its circular RC3 orbit about Ceres (13,500 km altitude, polar inclination, ascending node at local midnight) on April 23. I’ll attempt to pass along subsequent plots reflecting SEP thrusting leading to RC3 as they become available. -Dan
    Here is a link to the original ATIG #66 email file.
  • ATIG_065__2015_05_21 [May 21, 2015] An Op-Ed On Our Headlong Rush To Mars
    ATIG Members- In an attempt to put my essay on the AM II report in a broader context, I’m drafting an op-ed intended for publication in Space News (see the attached PDF file). It’s arguable that risks associated with Apollo Moon landings were justified by national prestige during the Cold War. I see nothing approaching this level of justification for taking even bigger risks in sending humans to Mars using an “affordable”, minimalist architecture. From bitter experience in the Shuttle Program, I’ve learned to appreciate affordability not just in monetary terms. There’s a human cost to affordability too. I welcome feedback on this op-ed. In particular, let me know if you’ve found any “unobtainium” on Mars only humans can extract. -Dan
    [FBCtheSequelR2A.pdf, 3 pages, 90 KB]
    From: Daniel Adamo <adamod@earthlink.net>
    Date: Tue, 14 Apr 2015 12:04:40 -0700
    Conversation: An Essay Commenting On The AM II Report
    Subject: An Essay Commenting On The AM II Report
    ATIG Members- I became aware of the second in a series of Affording Mars workshops (AM II) when its proceedings and findings were reviewed at the Future In-Space Operations (FISO) telecon of 4 February 2015. You can download charts and an audio transcript of this telecon at http://spirit.as.utexas.edu/%7Efiso/telecon/Thronson-Cassady_2-4-15/.
    The FISO presentation refers its audience to an AM II report. Since I took issue with much of the presentation’s material, I felt compelled to review the report in detail. My commentary from this review is attached in the subject essay. Your feedback on the essay is invited, and you are welcome to share it with stakeholders and other interested parties in your network. Please note I’ve already sent the essay to all the report’s editors whose email addresses I could find. I invite feedback from all essay readers, and I hope this dialog helps foster future workshops with greater integrity and ability to build a broader, more informed consensus on the why/how/when of human Mars exploration. -Dan
    PS: if your organization would like to hear more about the “why” or the “how” of human Mars exploration, I’d be willing to personally share my research on either subject in a one-hour presentation. All I ask in compensation is reimbursed travel expenses.
    Here is a link to the original ATIG #65 email file.
  • ATIG_064__2015_04_14 [April 14, 2015] An Essay Commenting On The AM II Report
    ATIG Members- I became aware of the second in a series of Affording Mars workshops (AM II) when its proceedings and findings were reviewed at the Future In-Space Operations (FISO) telecon of 4 February 2015. You can download charts and an audio transcript of this telecon at http://spirit.as.utexas.edu/%7Efiso/telecon/Thronson-Cassady_2-4-15/. The FISO presentation refers its audience to an AM II report. Since I took issue with much of the presentation’s material, I felt compelled to review the report in detail. My commentary from this review is attached in the subject essay. Your feedback on the essay is invited, and you are welcome to share it with stakeholders and other interested parties in your network. Please note I’ve already sent the essay to all the report’s editors whose email addresses I could find. I invite feedback from all essay readers, and I hope this dialog helps foster future workshops with greater integrity and ability to build a broader, more informed consensus on the why/how/when of human Mars exploration. -Dan
    [AffordingMarsIIcommentaryR0.pdf, 13 pages, 199 KB]
    PS: if your organization would like to hear more about the “why” or the “how” of human Mars exploration, I’d be willing to personally share my research on either subject in a one-hour presentation. All I ask in compensation is reimbursed travel expenses.
    Here is a link to the original ATIG #64 email file.
  • ATIG_063__2015_04_04 [April 4, 2015] Re: “Dawn” Achieves Ceres Orbit
    ATIG Members- Updating Dawn’s approach to (1) Ceres, the attached plot of Ceres-centered motion has SEP thrusting modeled into the mid-April time frame. This plot is viewed from Ceres’ equatorial plane in a direction looking “up” in the plot sent March 8. From the updated trajectory, SEP thrusting to achieve Dawn approach over Ceres’ north rotational pole is evident. Planned SEP thrusting in late April (not modeled in this plot’s ephemeris) will achieve a circular “RC3” orbit at 13,500 km altitude on April 23. You can read more about Dawn’s Ceres approach at http://dawnblog.jpl.nasa.gov/?p=2437. -Dan [CeresAppR2.pdf, 1 page, 93 KB]
    From: Daniel Adamo <adamod@earthlink.net>
    Date: Sun, 08 Mar 2015 21:45:51 -0700
    Conversation: “Dawn” Achieves Ceres Orbit
    Subject: “Dawn” Achieves Ceres Orbit
    ATIG Members- About the time most of us in the U.S. were arising on Friday morning, March 6, the Dawn spacecraft was achieving orbit about dwarf planet asteroid (1) Ceres. Because Dawn uses solar electric propulsion (SEP), its thrust duty cycles are highly flexible and equally uncertain because of the low accelerations exerted. The attached plot of Dawn’s Ceres-centered motion depicts orbit capture, but SEP thrusting doesn’t appear to be modeled much after March in the associated ephemeris posted March 6 to http://ssd.jpl.nasa.gov/?horizons. According to http://dawnblog.jpl.nasa.gov/2015/03/06/dawn-journal-march-6/, Dawn should be in its circular RC3 orbit about Ceres (13,500 km altitude, polar inclination, ascending node at local midnight) on April 23. I’ll attempt to pass along subsequent plots reflecting SEP thrusting leading to RC3 as they become available. -Dan
    Here is a link to the original ATIG #63 email file.
  • ATIG_062__2015_03_23 [March 23, 2015] Possible Post-Pluto Flybys For “New Horizons”
    ATIG Members- Last October, I first learned HST had discovered Kuiper Belt objects (KBOs) potentially accessible to New Horizons (NH) following its Pluto flyby on 2015 July 14. The news came to me in a report by NH Principal Investigator, Alan Stern (see http://pluto.jhuapl.edu/News-Center/PI-Perspectives.php?page=piPerspective_10_23_2014). Unfortunately, the KBO flyby candidates were referred to as “PT1”, “PT2”, and “PT3” in the article. This is not standard provisional nomenclature for small bodies in the solar system, so I wasn’t able to study potential KBO flyby trajectories at that time. My appeal for meaningful identification of the KBO flyby candidates was sent to <NewHorizons@jhuapl.edu> on 2014 October 23, but no response was received. Thanks to some help from NASA’s Small Bodies Assessment Group (SBAG), it now appears the candidates were only informally identified following their discoveries because anybody with access to the HST observations had insufficient skills or time to reduce those observations into orbit solutions. This month’s 46th Lunar and Planetary Science Conference apparently reordered some priorities, and orbit solutions are now available for the only 2 viable KBO flyby candidates remaining: 2014 MU69 and 2014 PN70. My assessment of KBO flyby prospects for NH is documented in the attached 2 PDF files. One PDF documents the 2014 MU69 flyby option, and one PDF documents the 2014 PN70 flyby option. In each PDF, a zoomed-in heliocentric trajectory plot is followed by two pork chop charts (PCCs). The first PCC tabulates post-Pluto change in velocity magnitude (Dv) required to achieve KBO intercept from the coasted NH trajectory. The second PCC tabulates the resulting flyby speed with respect to the KBO. Boxed cells in the PCCs pertain to the corresponding plotted flyby case. Other than KBO intercept trajectories I generated as heliocentric conics, all NH and KBO data are from ephemerides computed by JPL’s Horizons server at http://ssd.jpl.nasa.gov/?horizons. You can read more about New Horizons planning for Pluto flyby and thereafter from downloadable charts at http://www.lpi.usra.edu/sbag/new_horizons/. Enjoy! -Dan
    [NHto2014 MU69.pdf, 127 KB, 3 pages, NHto2014 PN70.pdf, 125 KB, 3 pages]
    Here is a link to the original ATIG #62 email file.
  • ATIG_061__2015_03_08 [March 8, 2015] “Dawn” Achieves Ceres Orbit
    ATIG Members- About the time most of us in the U.S. were arising on Friday morning, March 6, the Dawn spacecraft was achieving orbit about dwarf planet asteroid (1) Ceres. Because Dawn uses solar electric propulsion (SEP), its thrust duty cycles are highly flexible and equally uncertain because of the low accelerations exerted. The attached plot of Dawn’s Ceres-centered motion depicts orbit capture, but SEP thrusting doesn’t appear to be modeled much after March in the associated ephemeris posted March 6 to http://ssd.jpl.nasa.gov/?horizons. According to http://dawnblog.jpl.nasa.gov/2015/03/06/dawn-journal-march-6/, Dawn should be in its circular RC3 orbit about Ceres (13,500 km altitude, polar inclination, ascending node at local midnight) on April 23. I’ll attempt to pass along subsequent plots reflecting SEP thrusting leading to RC3 as they become available. -Dan
    [CeresAppR1.pdf, 1 page, 131 KB]
    Here is a link to the original ATIG #61 email file.
  • ATIG_060__2015_01_02 [January 2, 2015] Hayabusa-2’s Odyssey: The First Leg
    ATIG Members- Happy 2015! Japan’s Hayabusa-2 robotic mission to visit and retrieve samples from near-Earth asteroid (162173) 1999 JU3 began with launch on 2014 Dec 3. The attached Sun-centered inertial plot illustrates coasted Hayabusa-2 motion during the first year following launch, together with that of Earth and Venus. The initial solar orbit for Hayabusa-2 has a semi-major axis of 1.002 AU, bringing it near to Earth a year after launch, as seen in the attached plot. Thanks to Hayabusa-2’s ion thrusters, the plot’s coasted trajectory is to undergo progressive modification in the coming months such that a close encounter with Earth will occur in late 2015. Orientation of a Sun-centered orbit plane can be specified by its inclination with respect to the ecliptic (IN) and by ecliptic longitude of its ascending node (ELAN). In the attached plot, Earth’s orbit coincides with the ecliptic plane, and the arrow pointing rightward from the Sun annotates the direction toward zero ecliptic longitude. The following table indicates Hayabusa-2’s current orbit is very nearly coplanar with that of 1999 JU3.

    Orbit        IN (deg) ELAN (deg)
    Hayabusa-2   6.8      250.5
    1999 JU3     5.9      251.6

    As dotted blue lines projecting position onto the ecliptic plane indicate in the attached plot, Hayabusa-2’s current descending node is very close to the ecliptic longitude Earth occupies around December 3. On 2015 Dec 3.0 UTC, Earth’s ecliptic longitude will be 70.259 deg, very near the descending node for 1999 JU3 (251.6 – 180 = 71.6 deg). Current perihelion distance for Hayabusa-2 is 0.915 AU, again very close to 1999 JU3’s value of 0.963 AU. Thus, the gravity assist imparted to Hayabusa-2 from a properly targeted Earth encounter around 2015 Dec 3.0 UTC will easily enable rendezvous with 1999 JU3, currently set for July 2018. The precise rendezvous date is largely dependent on how closely the trajectory following Earth gravity assist matches 1999 JU3’s semi-major axis of 1.190 AU and on how aggressively this residual is reduced by ion propulsion. All Hayabusa-2 and 1999 JU3 data provided in this narrative and its attached plot are traceable to JPL’s Horizons server. This facility is accessible at http://ssd.jpl.nasa.gov/?horizons. -Dan
    [CoastedHayabusa2.pdf, 1 page, 65.5 KB]
    Here is a link to the original ATIG #60 email file.

  • ATIG_059__2014_12_17 [December 17, 2014] Re: A Proposed Launch Performance Standard
    ATIG Members- Many thanks to those of you who commented on the standard. I’ve incorporated that feedback, together with additional research, into a white paper on this topic. It may be downloaded from the Space Enterprise Institute (SEI) website at http://www.spaceenterpriseinstitute.org/2014/12/an-objective-launch-vehicle-performance-standard/. The SEI site does require you to register as a user before you can obtain its free downloads. This requires a name and email address, neither of which must be valid. Registration information is intended to suppress spam on the site and is employed to send you emailed alerts when new SEI material becomes available. Happy holidays! -Dan
    From: Daniel Adamo <adamod@earthlink.net>
    Date: Sun, 07 Dec 2014 17:06:58 -0800
    Conversation: A Proposed Launch Performance Standard
    Subject: A Proposed Launch Performance Standard
    ATIG Members- Many of you who correspond with me on “rocket science” matters are familiar with my rant on absence of a performance standard for launch vehicles such that “apples versus apples” comparisons may be made. I couldn’t tell you if a Delta IV Heavy delivers more performance than an Ariane V because they launch from different locations into different orbits. There are also claims regarding “the most powerful rocket ever flown” floating around out there. Just how powerful is that compared to other launch vehicles? And what is meant by “power” anyway? Thrust at liftoff is likely a poor metric for what really counts: initial mass delivered to low Earth orbit by a single launch (IMLEO). So, here’s my proposed standard for an IMLEO-based launch performance metric. First, some relevant background is warranted. Forty-two years ago today, on 7 Dec 1972, a Saturn V launched the Apollo XVII mission from KSC LC 39A (28.608 deg N Lat, 80.604 deg W Lon, -32.0 m Alt) at an azimuth of 91.5 deg E of N. Some 11.9 min after launch, insertion into a 166.7 km altitude circular orbit (reckoned with respect to an Earth radius of 6378.2 km) was achieved. Inclination of this orbit was 28.526 deg. See Apollo: The Definitive Sourcebook (Orloff & Harland, 2006), p. 511 for these statistics. Additional data from the Sourcebook infer a total Apollo XVII vehicle mass of 140,345 kg at orbit insertion. This IMLEO achievement has never been surpassed by a single launch, whether from Earth’s surface or a carrier aircraft. Launch service providers with accurate simulation capabilities are invited to duplicate the Apollo XVII launch circumstances, achieve a similar orbit with their launch vehicle (whether operational or under design), and report their IMLEO values via email along with the launch vehicle configuration simulated. These IMLEO results will be cited with the proposed standard at http://spaceenterpriseinstitute.org/, facilitating an “apples versus apples” performance comparison between launch vehicles. I‘d be very interested in any commentary regarding the proposed standard. In particular, is anyone aware of a similar or somehow better standard? One data point I might contribute would be from a MacMECO simulation of a Shuttle launch into the Apollo XVII orbit. Just how much Orbiter mass can be inserted into this orbit without incurring a low level MPS cutoff? If I have to use OMS-2 to circularize at 166.7 km, that propellant will come out of the IMLEO I report. But I will report “useless” IMLEO mass like the Orbiter’s wings. -Dan
    Here is a link to the original ATIG #59 email file.
  • ATIG_058__2014_12_07 [December 7, 2014] A Proposed Launch Performance Standard
    ATIG Members- Many of you who correspond with me on “rocket science” matters are familiar with my rant on absence of a performance standard for launch vehicles such that “apples versus apples” comparisons may be made. I couldn’t tell you if a Delta IV Heavy delivers more performance than an Ariane V because they launch from different locations into different orbits. There are also claims regarding “the most powerful rocket ever flown” floating around out there. Just how powerful is that compared to other launch vehicles? And what is meant by “power” anyway? Thrust at liftoff is likely a poor metric for what really counts: initial mass delivered to low Earth orbit by a single launch (IMLEO). So, here’s my proposed standard for an IMLEO-based launch performance metric. First, some relevant background is warranted. Forty-two years ago today, on 7 Dec 1972, a Saturn V launched the Apollo XVII mission from KSC LC 39A (28.608 deg N Lat, 80.604 deg W Lon, -32.0 m Alt) at an azimuth of 91.5 deg E of N. Some 11.9 min after launch, insertion into a 166.7 km altitude circular orbit (reckoned with respect to an Earth radius of 6378.2 km) was achieved. Inclination of this orbit was 28.526 deg. See Apollo: The Definitive Sourcebook (Orloff & Harland, 2006), p. 511 for these statistics. Additional data from the Sourcebook infer a total Apollo XVII vehicle mass of 140,345 kg at orbit insertion. This IMLEO achievement has never been surpassed by a single launch, whether from Earth’s surface or a carrier aircraft. Launch service providers with accurate simulation capabilities are invited to duplicate the Apollo XVII launch circumstances, achieve a similar orbit with their launch vehicle (whether operational or under design), and report their IMLEO values via email along with the launch vehicle configuration simulated. These IMLEO results will be cited with the proposed standard at http://spaceenterpriseinstitute.org/, facilitating an “apples versus apples” performance comparison between launch vehicles. I‘d be very interested in any commentary regarding the proposed standard. In particular, is anyone aware of a similar or somehow better standard? One data point I might contribute would be from a MacMECO simulation of a Shuttle launch into the Apollo XVII orbit. Just how much Orbiter mass can be inserted into this orbit without incurring a low level MPS cutoff? If I have to use OMS-2 to circularize at 166.7 km, that propellant will come out of the IMLEO I report. But I will report “useless” IMLEO mass like the Orbiter’s wings. -Dan
    Here is a link to the original ATIG #58 email file.
  • ATIG_057__2014_08_26 [August 26, 2014] Launches From Brownsville, TX
    ATIG Members- My recent research on LEO launch trajectories from Brownsville, TX is documented in the attached white paper, and I hope you’ll find it interesting. A major source of information for this paper is an FAA environmental impact statement (EIS) on Brownville launches. Please note the EIS link provided in the paper’s footnote on p. 6 is clickable but has too many imbedded line breaks to work in my browser. When I copy-and-paste this URL into my browser, however, it works. As usual, I welcome feedback on the paper. But I also have an open issue with this research on which I’d like input. The EIS doesn’t appear to raise any range safety issues with Brownsville launches to LEO. But, as documented in my paper, second stage underspeeds could conceivably scatter debris over land, even at the most benign targeted LEO inclination documented in the EIS. Is the FAA aware of this possibility? The potential threat of land impact would not arise in U.S. airspace, and the threatened impact footprint might also lie well outside U.S. airspace in many cases. Would a second stage underspeed impact threat then be outside FAA’s regulatory jurisdiction? If so, would any Federal agency have regulatory authority over this scenario? On request, I’ll keep the source of any feedback/input anonymous. -Dan
    [B’villeLaunchesR0.pdf, 6 pages, 285 KB]
    Here is a link to the original ATIG #57 email file.
  • ATIG_056__2014_08_17 [August 17, 2014] To Explore Or Pioneer?
    ATIG Members- You’ll recall my critique of the NAS Pathways to Exploration report. As with most critiques, it had to ramble a bit. Attached is an initial op-ed draft, ultimately targeted for Space News publication, that’s more focused on how I feel NASA’s HSF strategy needs to change. I won’t be sending this off for publication until next week in order to collect feedback from you and others. Many thanks for whatever you care to send. -Dan
    [ExploreOrPioneerOpEdR0.pdf, 3 pages, 94 KB]
    Here is a link to the original ATIG #56 email file.
  • ATIG_055__2014_07_20 [July 20, 2014] “Pathways” Critique
    ATIG Members- Attached is the latest draft of a critique I’ve written on last month’s National Academies Press publication Pathways to Exploration–Rationales and Approaches for a U.S. Program of Human Space Exploration. Your questions and comments on this critique and the Pathways report are invited. -Dan
    [PathwaysCommentaryR2.pdf, 9 pages, 178 KB]
    Here is a link to the original ATIG #55 email file.
  • ATIG_054__2014_07_09 [July 9, 2014] Selenocentric Distant Retrograde Orbits (SDROs) Paper
    ATIG Members- Earlier today, the attached paper was submitted to the 2014 AIAA/AAS Astrodynamics Specialist Conference (see http://www.aiaa-space.org/), a segment of AIAA’s SPACE 2014 Conference. A good portion of this paper was first distributed in the ATIG upload of 15 September 2013 PDT. The conference paper documents additional research concerning SDRO applications other than as a destination for redirected asteroids. Comments and questions on the paper are welcome. This publication has been approved by NASA-GSFC for public distribution. -Dan
    [InnovativeSDROsR6A.pdf, 19 pages, 1.6 MB]
    Here is a link to the original ATIG #54 email file.
  • ATIG_053__2014_05_07 [May 7, 2014] STS-16
    ATIG Members- No, this isn’t a blast from the past or a reenactment of the STS 51-D mission. It’s the return-to-flight for students at Russell Elementary School in Smyrna, GA. Their 28-hour “long sim” begins this Thursday, May 8. A YouTube broadcast schedule for the simulation and associated links can be accessed at http://russellroadrunners.typepad.com/space/youtube-broadcast-schedule.html. Back in the 1990s, student-run simulations like this were being performed regularly across the U.S., primarily in middle schools and high schools. They promoted interdisciplinary STEM education through the motivation of creative applied study, together with fulfillment from teamwork and mission accomplishment, before the acronym was even invented. Over the next decade, however, “teach to test” and the funding shortfall from No Child Left Behind left little time or financial support for these simulations. It’s my sincere hope that STS-16 will mark a turnaround in this trend. I‘d be interested in your comments about the Russell Space Team and their latest mission, particularly if you can watch some of their YouTube broadcasting. If you advocate space exploration, this is the future. -Dan
    “That the powerful play goes on, and you may contribute a verse.” -Walt Whitman
    Here is a link to the original ATIG #53 email file.
  • ATIG_052__2014_03_25 [March 25, 2014] Aquarius Proposal
    ATIG Members- Attached is a reasonably mature draft proposal for a water-based interplanetary human transport architecture. Trajectory designs in Section III make repeated use of the “aid” from the last ATIG upload on 27 January. My co-author Dr. Jim Logan and I hope this proposal helps human spaceflight stakeholders focus on a synergistic interplay of technologies and strategies critical to a sustainable presence far beyond low Earth orbit. As always, your questions and comments are welcome. -Dan
    [AquariusProposalR2.pdf, 34 pages, 1.5 MB]
    Here is a link to the original ATIG #52 email file.
  • ATIG_051__2014_01_27 [January 27, 2014] An Aid To Interplanetary Trajectory Design
    ATIG Members- I hope you’re enjoying a happy and prosperous 2014. This year, I find myself designing yet another precision round-trip trajectory from Earth to Mars and back. I expect to be sharing details of this design and its associated mission concept with you in the near future. During the patched conic phase of interplanetary trajectory design, I’ve found planet-centered departure or arrival hyperbolic trajectories can often be conveniently defined using asymptotic velocity imposed by the heliocentric transfer trajectory, together with specified periapsis distance and declination. The attached PDF details how to define and sample planet-centered hyperbolic trajectories using these data in a variety of mission design contexts. For those wishing to implement this technique, a numeric example is included for the context of arrival at Mars. As always, questions and comments on the attached documentation are welcome. -Dan
    [HyperDef+Samp.pdf, 7 pages, 1.6 MB]
    Here is a link to the original ATIG #51 email file.
  • ATIG_050__2013_11_02 [November 2, 2013] Potentially Hazardous Object (PHO) 2013 TV135
    ATIG Members- The attached white paper details a preliminary analysis of collision prospects between near-Earth object 2013 TV135 and Earth in year 2032. Such events play out very much in the same way as do potential collisions between ISS and debris orbiting Earth. The major difference is possible interplanetary collisions with Earth are typically first predicted decades in advance of impact, while those threatening ISS are rarely forecast more than a few days before closest approach. In both cases, collision probability Pc typically increases before it suddenly drops to zero, and statistics behind this behavior are explained in the paper. Of course, the typical ISS debris avoidance impulse of about 1 m/s would be unthinkably difficult to impart to the Earth. In the unlikely event 2013 TV135 Pc approaches near-certain levels, it would have to be diverted or exploded to avert an impact currently estimated at 3250 megatons. October 31’s Pc estimate for 2013 TV135 collision with Earth on 26.36 August 2032 UT is 0.00016, or 1-in-6250. At this Pc level, an ISS avoidance maneuver would be considered near-mandatory, but planning and executing such a maneuver can take a day or more with at most 3 days’ notice before potential collision. We have about a decade to refine 2013 TV135’s orbit before any worst-case scenario would precipitate action to mitigate collision with Earth. As always, feedback on this paper is invited. -Dan
    [PHO2013 TV135r1.pdf, 7 pages, 377 KB]
    Here is a link to the original ATIG #50 email file.
  • ATIG_049__2013_09_16 [September 16, 2013] Selenocentric Distant Retrograde Orbits (SDROs)
    ATIG Members- As many of your are aware, an SDRO is the intended end state for NASA’s contemplated Asteroid Redirect Mission (ARM). Earlier this year, I was in discussions with some of you regarding just how distant and how stable ARM’s SDRO would be. The attached white paper will hopefully answer these questions and make more clear the nature of SDROs. I welcome feedback from anyone who cares to read it. The attached PDF is bookmarked to facilitate navigation. I’ve tested all URLs to verify they’re functional, but the one in the second footnote on p. 1 won’t work with my web browser because line wrapping in Acrobat inserts some superfluous characters when it’s clicked. The URL reads correctly in the PDF and is reproduced here as http://www.nasa.gov/pdf/756122main_Asteroid%20Redirect%20Mission%20Reference%20Concept%20Description.pdf in case anyone wants to download this document but can’t use the PDF’s URL. Enjoy! -Dan
    [DROassessmentsR0.pdf, 24 pages, 2.9 MB]
    Here is a link to the original ATIG #49 email file.
  • ATIG_048__2013_09_07 [September 7, 2013] LADEE Trajectory to LOI
    ATIG Members- Friday night, NASA’s Lunar Atmosphere and Dust Environment Explorer (LADEE) spacecraft was launched from the Wallops Flight Facility by a Minotaur V rocket on a month-long multi-orbit trajectory to the Moon. Liftoff was on time September 6 at 11:27 PM EDT, and the reported trans-lunar trajectory was nominal. I’m therefore enclosing Earth-centered and Moon-centered inertial trajectory plots of the planned nominal trajectory leading to lunar orbit insertion (LOI) on October 6. Data supporting these plots were posted to JPL’s Horizons ephemeris service on August 30. According to a report posted to http://www.nasa.gov/LADEE/#.Uis62OB0org at 3:40 AM EDT on September 7, mission controllers are working an anomalous shutdown of LADEE’s attitude control reaction wheels, but communications with the spacecraft are still being maintained. The nominal trans-lunar trajectory appears to be very flexible in achieving LOI, so there is ample time to work this problem. If any significant trajectory updates are posted, I’ll make every effort to pass along updated plots. -Dan
    [LADEEprelaunchGeo.gif, 1 page, 150 KB, LADEEprelaunchSel.gif, 1 page, 110 KB]
    Here is a link to the original ATIG #48 email file.
  • ATIG_047__2013_07_24 [July 24, 2013] Reusable Infrastructure In Earth Orbit Supporting Multiple Mars Departures
    ATIG Members- I‘m sure many of you are aware of space architectures, such as propellant depots, offering support to human spaceflight (HSF) beyond low Earth orbit (LEO). Such infrastructure would likely provide more return on investment if it could be reused to facilitate multiple departures from LEO bound for deep space. Earlier this year, I researched how reusable infrastructure in Earth orbit might assemble and service Mars-bound payloads during successive departure seasons in 2020 and 2022. The attached PDF file documents this research and its findings. It is bookmarked to aid navigation. Your questions, suggestions, and discussion of this work are invited. -Dan
    [MultipleMarsDeparturesR1.pdf, 24 pages, 1.6 MB]
    Here is a link to the original ATIG #47 email file.
  • ATIG_046__2013_06_15 [June 15, 2013] Rendezvous Endgame
    ATIG Members- About 8 hours before ATV-4 docked with ISS at 7:07 AM PDT on June 15, the attached image was obtained from my home south of Salem, Oregon. Both spacecraft are recorded moving southeastward past the star Deneb in the constellation Cygnus. The 30-second exposure began at 11:14:42 PM PDT on June 14 with ISS leading ATV-4 at a point near its closest approach to Deneb. For those unfamiliar with constellations, I’ve “connected the dots” for Cygnus, alias The Northern Cross, using faint gray lines. Note how much closer the two trails are to overlaying each other in this late phase of rendezvous than they were in the image obtained a week earlier. Because ISS elevation above the horizon is similar in both images, about 40 degrees, the ATV-4 trail has shifted closer to that of ISS in the later image due to its increased orbit altitude. This is a typical signature in “rendezvous from below and behind” operations. In the endgame, the spacecraft about to dock with ISS progressively reduces its catch-up rate by incrementing its orbit altitude to more closely match that of ISS. By carefully timing these increments, ATV-4 achieved an altitude match just as it caught up with ISS, allowing docking operations to proceed safely at low relative speeds. Yet another faint unidentified satellite trail is visible in the attached image. For scale, assign angular distance d to the apparent separation between Deneb and the star Gamma Cygni at which the two Northern Cross members intersect. From Gamma Cygni, proceed in the 4 o’clock direction about 0.7 d to the trail, which is about 0.2 d in length. Because the trail is so short compared to those of ISS and ATV-4, it’s undoubtedly from a satellite at much higher altitude. Congratulations to ESA for a successful (and picturesque) rendezvous and docking with ISS! -Dan
    [IMG_1156ann.JPG, 645 KB]
    From: Daniel Adamo <adamod@earthlink.net>
    Date: Sat, 08 Jun 2013 11:36:36 -0700
    Conversation: Highway In The Sky (Speed Limit: 7.7 km/s)
    Subject: Highway In The Sky (Speed Limit: 7.7 km/s)
    ATIG Members- The attached photo was taken from my home looking north toward the city of Salem, Oregon with the state capitol about 10 km away, so please forgive a little light pollution. It shows an early stage of the European Space Agency’s (ESA’s) Automated Transfer Vehicle-4 (ATV-4, christened Albert Einstein, see http://esamultimedia.esa.int/HSO/Publications/ATV4-EN/) rendezvous with the International Space Station (ISS). The photo’s exposure began on June 7 at 10:28:59 PM PDT when only ATV-4 (dimmer, lower trail) was in the camera’s field of view, and exposure was terminated 55 sec later when only ISS (brighter, higher trail) was in the field of view. Because the two spacecraft are orbiting in nearly the same plane with ATV-4 at a slightly lower altitude and higher speed, their trails are parallel but displaced during the exposure. Orbit motion among the stars is down and to the right in the photo, which shows a maple and a fir tree in silhouette against Salem’s sky-glow at bottom. There’s also a very faint trail at lower left running nearly perpendicular to that of ISS, but I have no idea what Earth satellite caused it. For those unfamiliar with constellations, I’ve “connected the dots” for Ursa Minor, alias The Little Dipper, using faint gray lines. The star at the end of the Dipper’s handle, and closest to the end of the ISS trail, is Polaris. Launched on June 5 at 2:52 PM CDT, ATV-4’s docking with ISS is planned for June 15 at 6:46 AM PDT. The attached June 7 PDT photo catches ATV-4 just after it had “lapped” ISS and moved ahead of it in orbit. On the previous PDT evening, ATV-4 was on the other side of Earth from ISS, making a single exposure capturing both spacecraft impossible for Earthbound photographers. The following table shows daily differences in the times ISS and ATV-4 appear in Salem’s sky after sunset. This Dt is reckoned by subtracting the ISS time from the ATV-4 time for a particular PDT evening, so a negative value implies ISS trails ATV-4. The concept of trailing or leading degenerates near +45 min or -45 min Dt when ISS and ATV-4 are on opposite sides of the Earth.

    PDT Date    Dt (min)
    June 5      +10
    June 6      -44
    June 7      0
    June 8      +44
    June 9      -11
    June 10     +40
    June 11     -3
    June 12     -43
    June 13     +16
    June 14     0

    From data in the foregoing table, ATV-4 can be inferred to pass beneath ISS on multiple occasions at roughly 2-day intervals prior to about a day before docking. If you’re interested in sighting opportunities for ISS, ATV-4, or various other satellites from your location, point your web browser at http://spaceflight.nasa.gov/realdata/sightings/index.html to obtain predictions. Wishing you clear skies! -Dan
    Here is a link to the original ATIG #46 email file.

  • ATIG_045__2013_06_08 [June 8, 2013] Highway In The Sky (Speed Limit: 7.7 km/s)
    ATIG Members- The attached photo was taken from my home looking north toward the city of Salem, Oregon with the state capitol about 10 km away, so please forgive a little light pollution. It shows an early stage of the European Space Agency’s (ESA’s) Automated Transfer Vehicle-4 (ATV-4, christened Albert Einstein, see http://esamultimedia.esa.int/HSO/Publications/ATV4-EN/) rendezvous with the International Space Station (ISS). The photo’s exposure began on June 7 at 10:28:59 PM PDT when only ATV-4 (dimmer, lower trail) was in the camera’s field of view, and exposure was terminated 55 sec later when only ISS (brighter, higher trail) was in the field of view. Because the two spacecraft are orbiting in nearly the same plane with ATV-4 at a slightly lower altitude and higher speed, their trails are parallel but displaced during the exposure. Orbit motion among the stars is down and to the right in the photo, which shows a maple and a fir tree in silhouette against Salem’s sky-glow at bottom. There’s also a very faint trail at lower left running nearly perpendicular to that of ISS, but I have no idea what Earth satellite caused it. For those unfamiliar with constellations, I’ve “connected the dots” for Ursa Minor, alias The Little Dipper, using faint gray lines. The star at the end of the Dipper’s handle, and closest to the end of the ISS trail, is Polaris. Launched on June 5 at 2:52 PM CDT, ATV-4’s docking with ISS is planned for June 15 at 6:46 AM PDT. The attached June 7 PDT photo catches ATV-4 just after it had “lapped” ISS and moved ahead of it in orbit. On the previous PDT evening, ATV-4 was on the other side of Earth from ISS, making a single exposure capturing both spacecraft impossible for Earthbound photographers. The following table shows daily differences in the times ISS and ATV-4 appear in Salem’s sky after sunset. This Dt is reckoned by subtracting the ISS time from the ATV-4 time for a particular PDT evening, so a negative value implies ISS trails ATV-4. The concept of trailing or leading degenerates near +45 min or -45 min Dt when ISS and ATV-4 are on opposite sides of the Earth.

    PDT Date    Dt (min)
    June 5      +10
    June 6      -44
    June 7      0
    June 8      +44
    June 9      -11
    June 10     +40
    June 11     -3
    June 12     -43
    June 13     +16
    June 14     0

    From data in the foregoing table, ATV-4 can be inferred to pass beneath ISS on multiple occasions at roughly 2-day intervals prior to about a day before docking. If you’re interested in sighting opportunities for ISS, ATV-4, or various other satellites from your location, point your web browser at http://spaceflight.nasa.gov/realdata/sightings/index.html to obtain predictions. Wishing you clear skies! -Dan
    [IMG_1144annotated.JPG, 521 KB]
    Here is a link to the original ATIG #45 email file.

  • ATIG_044__2013_05_18 [May 18, 2013] A Special Earthlike Orbit: NEO 2013 BS45
    ATIG Members- At heliocentric (a, e) coordinates (0.998 AU, 0.084) on the V-plot sent last month is the newly discovered NEO 2013 BS45. With a semi-major axis nearly the same as Earth’s, this NEO’s heliocentric phase rate with respect to Earth is so small that some very strange things happen to its orbit as it closes in on our planet. Read all about 2013 BS45’s remarkable orbit in the attached PDF file. Could a small NEO in an orbit like 2013 BS45’s be captured and retrieved by a robotic spacecraft with ion engines? Such a target would not be easy to find with enough lead time to launch a rendezvous mission before it escapes the reach of our current retrieval technology. -Dan
    [Horseshoe2013bs45r3.pdf, 10 pages, 968 KB]
    From: Daniel Adamo <adamod@earthlink.net>
    Date: Mon, 22 Apr 2013 09:39:16 -0700
    Conversation: Near-Earth Objects (NEOs) In Earthlike Orbits
    Subject: Near-Earth Objects (NEOs) In Earthlike Orbits
    ATIG Members- The attached PDF file is effectively a 2-page caption for the “V-plot” graphic at its conclusion. To clearly view annotations on this graphic, you’ll need a zoom factor of about 250%. As humanity begins to explore the most accessible interplanetary destinations in an era prior to the first comprehensive NEO survey, a current V-plot is akin to maps of the New World published circa 1500 AD. As you study the V-plot, be sure to note the location of 2013 BS45. This recently discovered NEO is in a very interesting orbit and will be the subject of an ATIG upload in the next month or so. -Dan
    Here is a link to the original ATIG #44 email file.
  • ATIG_043__2013_04_22 [April 22, 2013] Near-Earth Objects (NEOs) In Earthlike Orbits
    ATIG Members- The attached PDF file is effectively a 2-page caption for the “V-plot” graphic at its conclusion. To clearly view annotations on this graphic, you’ll need a zoom factor of about 250%. As humanity begins to explore the most accessible interplanetary destinations in an era prior to the first comprehensive NEO survey, a current V-plot is akin to maps of the New World published circa 1500 AD. As you study the V-plot, be sure to note the location of 2013 BS45. This recently discovered NEO is in a very interesting orbit and will be the subject of an ATIG upload in the next month or so. -Dan
    [Vplot2013mar11r1.pdf, 3 pages, 356 KB]
    Here is a link to the original ATIG #43 email file.
  • ATIG_042__2013_03_02 [March 2, 2013] Chelyabinsk Bolide Trajectory Reconstruction
    ATIG Members- Greetings from sunny (today at least) Salem, Oregon! I hope you’ll enjoy my first ATIG contribution from the Pacific Northwest in the attached PDF file. It is inspired by celestial events on February 15, but the fog surrounding those events only started to clear about a week ago. Another report released earlier today can be found at http://neo.jpl.nasa.gov/news/fireball_130301.html. -Dan
    [ChelyabinskBolideReconR1.pdf, 3 pages, 144 KB]
    Here is a link to the original ATIG #42 email file.
  • ATIG_041__2012_11_03 [November 3, 2012] 2012 UV136 And Its Subjective Accessibility For HSF
    ATIG Members- Last month, yet another near-Earth object (NEO) was discovered in an orbit very similar to Earth’s. As the attached report details, this NEO is highly accessible for human space flight (HSF) over the next decade or so, but that accessibility is fleeting. Your comments are welcome. -Dan
    [2012 UV136discoveryR1.pdf, 4 pages, 264 KB]
    Here is a link to the original ATIG #41 email file.
  • ATIG_040__2012_10_17 [October 17, 2012] Last Friday’s Flyby
    ATIG Members- Last Friday, 12 October, another bit of interplanetary flotsam flew between us and the Moon. According to best estimates, it’ll be back to visit us 12 October 2017. On that occasion, it could reach a perigee distance anywhere from 464,700 km (just outside the Moon’s orbit) to 13,000 km (well inside GEO altitude). Be careful out there! -Dan
    [GravityAssistTo2012 TC4r1.pdf, 3 pages, 237 KB]
    Here is a link to the original ATIG #40 email file.
  • ATIG_039__2012_09_29 [September 29, 2012] Comet ISON
    ATIG Members- If Comet ISON’s discovery is news to you, the article at http://www.space.com/17762-newfound-comet-dazzling-2013-display-c2012s1.html provides useful background. As with any long-period comet coming to its first perihelion in human history, ISON could be a dazzler or a dud. Nevertheless, I hope the attached PDF file will convey an appreciation for its orbit and Earthly viewing geometry. May we all require sunglasses to see it near perihelion! As some of you already know, my wife and I are on a path to relocation in Salem, Oregon late this year, fulfilling a retirement vision of ours after years of searching the Willamette Valley for our dream home. You can perhaps appreciate my motivation by browsing to http://www.redfin.com/OR/Salem/8119-Kloshe-Ct-S-97306/home/26352434. This is indeed the land of milk and honey (if you can manage a few brambles and gophers). I intend to retain my EarthLink address through my relocation, ISPs permitting. And, as most of you can attest, I never leave my trajectory analysis tools behind. Keep in touch! -Dan
    [CometISONin2013+14.pdf, 2 pages, 204 KB]
    Here is a link to the original ATIG #39 email file.
  • ATIG_038__2012_08_10 [August 10, 2012] A Notional Round Trip to EML2
    ATIG Members- Some of you are aware of trajectory studies being conducted by NASA-JSC’s Flight Dynamics Division in which the translunar libration point (EML2) is the Orion crew’s destination. During an educational outreach effort at JSC this month, a notional Orion mission to EML2 was presented to secondary school teachers from around the U.S. This presentation consisted of a descriptive illustrated PDF file, together with a 3-D simulation rendered by Celestia. The simulation was subsequently turned into a QuickTime movie of 6 min 49 sec duration. Both the PDF file and QuickTime movie are archived at https://spideroak.com/browse/share/DanAdamo/EML2roundTrip as a downloadable package about 120 MB in size. I hope you enjoy this flight of fancy and look forward to any comments you may have. -Dan
    [AIAA is also providing links to those two files here: EML2roundTripR1.mov, 128 MB, 6:49 (minutes:seconds), EML2roundTripR2.pdf, 6 pages, 456 KB.]
    Here is a link to the original ATIG #38 email file.
  • ATIG_037__2012_08_01 [August 1, 2012] Apollo Hardware In Solar Orbit
    ATIG Members- I‘ve talked with some of you about a consulting contract I’ve been working this year under which I’ve reconstructed Apollo Program trajectories pertaining to jettisoned hardware placed in solar orbit. The primary deliverable for this contract is a report describing reconstruction methodology and results. My JPL customer has kindly granted permission to distribute the finalized report without restriction, so it’s attached. The tentative plan for Space Launch System (SLS) upper stage disposal is similar to that used on Saturn IV-B (S-IVB) upper stages during the Apollo 8 through 12 missions and documented in the report. Back in the Apollo Era, S-IVB stages could be tracked post-TLI only as long as batteries could power the onboard radio transponder (less than a day). Consequently, these stages were lost well before they entered interplanetary space. Today, the situation is different. Planetary radars at Goldstone, California and Arecibo, Puerto Rico can likely skin track an SLS upper stage for weeks after TLI. This could result in a sufficiently accurate orbit to support recovery when the upper stage returns to Earth’s vicinity. Because upper stages disposed in interplanetary space tend to enter solar orbits very similar to Earth’s, there is high value in maintaining knowledge of their trajectory status over time. If this is done, the stages will not be mistaken for potentially hazardous objects (PHOs) threatening Earth impact. Nor will they be mistaken for highly accessible near-Earth asteroids (NEAs) warranting robotic or human visits. I‘m considering writing an op-ed advocating funding planetary radar tracking of disposed SLS upper stages as they head for solar orbit. If anyone has comments or information on this concept they can share, I’d appreciate hearing from you. -Dan
    [ApolloEarthDeparturesR7.pdf, 49 pages, 3.3 MB]
    Here is a link to the original ATIG #37 email file.
  • ATIG_036__2012_07_24 [July 24, 2012] Re: Mars Science Lab (MSL) Entry/Descent/Landing (EDL)
    ATIG Members- With help from one among our ranks, I’ve traced the 3-min skew to an error on my part in converting events from solar system barycentric time to UTC. As penance, I shall attend this Friday’s Trajectory Think Tank discourse on time measurement by JSC-DM/Brian Kubena. This error has been corrected in the attached “r1” revision to my 22 July upload, which is hereby completely superseded. Happy landings! -Dan
    [MSL’sEDLr1.pdf, 3 pages, 251 KB]
    From: Daniel Adamo <adamod@earthlink.net>
    Date: Sun, 22 Jul 2012 08:27:32 -0500
    Conversation: Mars Science Lab (MSL) Entry/Descent/Landing (EDL)
    Subject: Mars Science Lab (MSL) Entry/Descent/Landing (EDL)
    ATIG Members- You’ll find attached my analysis of what I believe to be the latest and most authoritative MSL EDL data available to the public at this time. Those of us who attended JSC-DM/Gavin Mendeck’s excellent presentation on this topic at June 29’s Trajectory Think Tank will note EI (and presumably other events) in the attachment is about 3 min later than in Gavin’s Chart #10. I’m suspicious this time skew is by design and is an attempt to delay MSL landing in order to obtain better EDL real time data relay coverage. The relay function is provided through Mars Odyssey, which recently suffered a reaction wheel failure and may otherwise be unable to establish contact with MSL until after landing. I‘ve been unable to verify the 3-min skew is real beyond a well written 16 July report on the relay difficulty by Jonathan Amos at http://www.bbc.co.uk/news/science-environment-18861463. Reports at http://mars.jpl.nasa.gov/msl/news/whatsnew/ are terse and do not confirm or refute the skew’s existence. If anyone’s in a position to provide better EDL planning data to me, I’m willing to revise the attached PDF accordingly and distribute to ATIG. -Dan
    Here is a link to the original ATIG #36 email file.
  • ATIG_035__2012_04_22 [April 22, 2012] NEA to EML2
    ATIG Members- My apologies to those of you I’m contacting about the subject concept for the second time, but I’d like to share it with the broadest possible community. Many of you have already heard the hype surrounding launch of Planetary Resources on April 24. The science and engineering behind this corporate startup is likely documented in a Keck Institute for Space Studies (KISS) report available for download at http://kiss.caltech.edu/study/asteroid/asteroid_final_report.pdf. If this asteroid capture and return (ACR) venture becomes viable, EML2 may not be “just an empty point in space” by the time humans arrive there. -Dan
    Here is a link to the original ATIG #35 email file.
  • ATIG_034__2012_03_07 [March 7, 2012] Re: The Risk Corridor 
    ATIG Members- It seems Nature has supplied a timely footnote for my 2011 AG5 risk corridor analysis. Attached are heliocentric and geocentric plots spanning NEO 2012 DA14’s close Earth approach on 15 Feb 2013. Recent Horizons prediction data (reference ephemeris JPL#15) for that event appear in the following table.

    Date (CT)               Body   CA Dist   MinDist   MaxDist   Vrel   TCA3Sg Nsigs   P_i/p
    A.D. 2013 Feb 15.81141  Earth  0.000182  0.000181  0.001436  8.195  73.09  2013.0  0.000000

    Converting CA Dist, MinDist, and MaxDist from AU to km units, I couldn’t help noticing the nominal perigee distance of 27,200 km is nearly the same as the minimum possible perigee (to 3-sigma confidence) of 27,100 km and yet is appreciably removed from the maximum possible perigee (to 3-sigma confidence) of 214,800 km. Perigee distance uncertainty is confirmed by TCA3Sg’s value. At 73.09 minutes, that’s a lot of potential Earth-relative motion! The attached geocentric plot gives geometric perspective on perigee distance uncertainty. The line of variations (LOV) is effectively the plotted trajectory, and it’s nearly perpendicular to Earth’s heliocentric velocity (directed roughly out of the plot at the viewer). Thus, variations in the time of perigee can affect perigee distance, but they can’t appreciably decrease the current best guess for that distance. So, as indicated by the P_i/p value, there is no credible prospect for Earth collision (nor for a risk corridor plot) associated with this approach. -Dan
    [2012 DA14hel#14.gif, 166 KB, 2012 DA14geo#15.gif, 138 KB]
    From: Daniel Adamo <adamod@earthlink.net>
    Date: Sun, 04 Mar 2012 15:43:58 -0600
    Conversation: The Risk Corridor
    Subject: The Risk Corridor
    ATIG Members- Arguably the most compelling reason for space exploration (human or robotic) is planetary defense from impact by potentially hazardous objects (PHOs), comprised of near-Earth objects (NEOs) and long-period comets. The attached white paper is motivated by NEO 2011 AG5’s possible Earth impact in 2040 (reference http://www.space.com/14683-big-asteroid-2011-ag5-threat-earth.html), which if it actually took place, would then be confined to a 15-km-wide locus of terrestrial locations called the risk corridor. A non-conventional risk corridor generation method documented by the paper is inspired by a strategy ATIG members familiar with Shuttle ascent/entry onboard state vector management will recognize: to correct a down-track navigation error (the most common type), simply modify the state vector time tag as appropriate. In applying this strategy to risk corridor computation, the time bias is varied to systematically sample a PHO’s one-dimensional uncertainty region for the subset of conditions resulting in Earth impact. I welcome feedback on this paper and its implications for planetary defense. -Dan
    Here is a link to the original ATIG #34 .eml (email) file.

  • ATIG_033__2012_03_04 [March 4, 2012] The Risk Corridor
    ATIG Members- Arguably the most compelling reason for space exploration (human or robotic) is planetary defense from impact by potentially hazardous objects (PHOs), comprised of near-Earth objects (NEOs) and long-period comets. The attached white paper is motivated by NEO 2011 AG5’s possible Earth impact in 2040 (reference http://www.space.com/14683-big-asteroid-2011-ag5-threat-earth.html), which if it actually took place, would then be confined to a 15-km-wide locus of terrestrial locations called the risk corridor. A non-conventional risk corridor generation method documented by the paper is inspired by a strategy ATIG members familiar with Shuttle ascent/entry onboard state vector management will recognize: to correct a down-track navigation error (the most common type), simply modify the state vector time tag as appropriate. In applying this strategy to risk corridor computation, the time bias is varied to systematically sample a PHO’s one-dimensional uncertainty region for the subset of conditions resulting in Earth impact. I welcome feedback on this paper and its implications for planetary defense. -Dan
    [RiskCorr2011 AG5r2.pdf, 8 pages, 319 KB]
    Here is a link to the original ATIG #33 email file.
  • ATIG_032__2012_01_31 [January 31, 2012] Re: Draft Phobos-Grunt Article
    ATIG Members- Looks like the 15 Jan landing date was reasonably accurate. Now if somebody can just figure out where the debris really ended up, or at least release some terminal observations without compromising U.S. space-based space surveillance capability. As some of you have already noticed, Lindley Johnson and I are cited in an article on inane Russian explanations for Phobos-Grunt’s failure by Jim Oberg (not something I’ll be putting on my résumé) at http://www.thespacereview.com/article/2016/1. One reviewer of my “R0” Phobos-Grunt draft article requested I look into a recovery strategy involving 4 TMI burns. The first two raise apogee, the third does a plane change at apogee to null the accumulated TMI steering angle targeting Mars, and the last burn achieves Earth departure. This strategy is akin to one developed by the Constellation Program to enable “anytime” Earth return from low lunar orbit. If I’ve done my Phobos-Grunt performance bookkeeping correctly, the 4-burn TMI would have enabled mission recovery as late as 9 days after launch. As you’ll recall from the R0 draft, a standard 2-burn TMI with simultaneous planar steering would have supported mission recovery for only 3 days after launch. The attached PDF incorporates the 4-burn TMI strategy (modeled as 3 impulses) in a new section beginning at the bottom of p. 8 and completely supersedes R0. Other changes to R0 are relatively minor. This “R1” draft is what I intend to submit before the 8 Feb newsletter deadline, but I’ll do my best to incorporate any feedback you may have. If it’ll expedite your review, I can send a PDF with all R1 redlines to an R0 baseline on request. Enjoy! -Dan
    [Phobos-GruntTMIr1.pdf, 11 pages, 989 KB]
    From: Daniel Adamo <adamod@earthlink.net>
    Date: Thu, 29 Dec 2011 20:33:27 -0600
    Conversation: Draft Phobos-Grunt Article
    Subject: Draft Phobos-Grunt Article
    ATIG Members- Attached is a draft article intended for publication in AIAA-Houston Section’s Jan-Feb 2012 newsletter (author deadline is 8 Feb). I believe this to be the most lucid account of when Phobos-Grunt could have departed Earth for Mars under at least two scenarios which became hopelessly confused during November 2011. Except for the “TBS” Phobos-Grunt orbit decay date on p. 2 (current predictions are converging on 15 Jan), I believe this draft is complete. Any corrections or suggestions you care to send are invited. -Dan
    Here is a link to the original ATIG #32 email file.
  • ATIG_031__2012_01_09 [January 9, 2012] X-37B Flyby of Tiangong-1
    ATIG Members- Welcome to 2012! Attached is a somewhat rambling account, but it’s to the point. Doing the analysis, I somehow felt the veil of secrecy about X-37B operations had been (legally) lifted to a degree, at least hypothetically. I’ll be interested in anyone’s reasoned take on whether or not you think the 10 January flyby will be on X-37B’s flight plan. -Dan
    [X-37Bflyby.pdf, 6 pages, 632 KB]
    Here is a link to the original ATIG #31 email file.
  • ATIG_030__2011_12_29 [December 29, 2011] Draft Phobos-Grunt Article
    ATIG Members- Attached is a draft article intended for publication in AIAA-Houston Section’s Jan-Feb 2012 newsletter (author deadline is 8 Feb). I believe this to be the most lucid account of when Phobos-Grunt could have departed Earth for Mars under at least two scenarios which became hopelessly confused during November 2011. Except for the “TBS” Phobos-Grunt orbit decay date on p. 2 (current predictions are converging on 15 Jan), I believe this draft is complete. Any corrections or suggestions you care to send are invited. -Dan
    [Phobos-GruntTMIr0.pdf, 8 pages, 965 KB]
    Here is a link to the original ATIG #30 email file.
  • ATIG_029__2011_12_18 [December 18, 2011] Comet Lovejoy Solar Graze
    ATIG Members- The attached account of last week’s solar graze is an attempt at public outreach which I’m also circulating among colleagues. From imagery posted at SpaceWeather.com and other sites, laypersons may be under the impression Comet Lovejoy tunneled through the Sun. A less geocentric perspective gives a clearer understanding. Feel free to share with others. Happy holidays to all! -Dan
    [LovejoyGraze.pdf, 2 pages, 154 KB]
    Here is a link to the original ATIG #29 email file.
  • ATIG_028__2011_12_06 [December 6, 2011] A Peek at “Cassini”
    ATIG Members- Attached is another astrodynamics draft article intended for the AIAA-Houston Section’s next newsletter. Comments and corrections are invited, as always. I’ve heard rumors Cassini may not make it to the planned mission termination date in 2017. Apparently JWST is consuming so much of NASA’s science budget that serious consideration is being given to shutting down operations for Cassini and other functioning missions this fiscal year. I resisted the temptation to lobby on Cassini’s behalf in the article and simply let a few pictures do the talking. Happy holidays! -Dan
    [CassiniAfter7yearsR0.pdf, 7 pages, 1.4 MB]
    Here is a link to the original ATIG #28 email file.
  • ATIG_027__2011_11_05 [November 5, 2011] A Salvo for the ATIG
    ATIG Members- Attached are 3 PDFs documenting recent research. The first relates to NEO 2005 YU55’s Earth encounter at 9.0 November 2011 UTC, and is the most perishable material. I hope you’ll agree this encounter has broader implications for planetary defense and interplanetary astronautics. This initial draft may morph into an article appearing in the AIAA-Houston Section’s newsletter a couple months hence. The next two PDFs are peer-reviewed references I’ve produced as follow-on actions from my 3 weeks as a volunteer mentor at JSC’s High School Aerospace Scholars (HAS) workshops this past summer. Some of you participated in this review, and I’m grateful for your help. An introduction to interplanetary trajectory design and mission analysis appears in the Interplanetary Cruising reference, while the Radiation Shielding reference discusses the interplanetary environment, NASA standards, and a possible mitigation strategy in that context. I hope you’ll find all this reference material useful and will be using it sooner than you may currently believe! As always, comments and corrections regarding the PDFs are welcome and appreciated. -Dan
    [2005 YU55,TheCycler.pdf, 3 pages, 224 KB, InterplanetaryCruisingR2.pdf, 17 pages, 1.8 MB, RadShieldingMassR2.pdf, 5 pages, 118 KB]
    Here is a link to the original ATIG #27 email file.
  • ATIG_026__2011_10_17 [October 17, 2011] Asteroid 2009 TM8
    ATIG Members I‘m impressed: after I sent out the notice at the bottom of this thread 2 years ago, one among us added an appropriate event to her calendar for today and has inquired what’s become of 2009 TM8. Good question, Pam! Just before noon CDT today, I polled JPL’s Small Bodies Database (SBDB) and found 2009 TM8’s record hasn’t received another observation since the 48 leading to its discovery. Because these observations extended over only 2 days (close to a 2-deg heliocentric arc), the integrity of the current 2008 TM8 orbit elements would be equivalent to those from low speed ground NAV tracking a Shuttle for half a minute. Indeed, the SBDB’s Orbital Condition Code (OCC) for this NEO is 6, meaning 2009 TM8 is effectively lost. According to Harvard’s Minor Planet Center, OCC = 6, is equivalent to a heliocentric downtrack error between 1692 and 7488 arc-seconds per decade. Consequently, in the two years since 2009 TM8 was discovered, its predicted heliocentric mean anomaly is probably in error from 0.1 to 0.4 deg. Since humanity insists on observing NEOs only from Earth, a very close approach by 2009 TM8 is required because its diameter is almost certainly less than 10 m. When mapped into a close-up geocentric viewing geometry, heliocentric position uncertainty places 2009 TM8 virtually anywhere in our sky this week. I‘ll be in touch with further details if this celestial needle in a haystack is rediscovered. Fortunately, an object less than 10 m in diameter won’t do much damage if it enters Earth’s atmosphere. -Dan
    From: Daniel Adamo <adamod@earthlink.net>
    Date: Wed, 21 Oct 2009 12:12:37 -0500
    Subject: Asteroid 2009 TM8
    ATIG Members- Last Friday evening Oct 16 CDT, yet another asteroid briefly came closer to Earth than the Moon. Flyby geometry for the interloper, provisionally designated 2009 TM8, is illustrated in the attached geocentric plot. With the Moon and Sun roughly to the left of Earth in the geocentric plot, 2009 TM8 crossed Earth’s heliocentric orbit ahead of our path around the Sun. Earth flyby geometry therefore caused 2009 TM8 to lose some heliocentric orbit energy. This is apparent from the heliocentric plot spanning 2009 and 2010. Note the shift to lower aphelion as the 2009 TM8 plot begins and ends. As of October 18, JPL’s orbit solution for 2009 TM8 contained 36 observations over a 2-day arc. By October 20, 48 observations had been processed over the same arc. Because (2009 TM8)’s Earth departure was toward the Sun, I’m speculating the observation arc won’t be extended later in time very much. The only significant improvement in the orbit solution would come from a serendipitous pre-discovery observation. Nevertheless, current knowledge of (2009 TM8)’s post-flyby heliocentric orbit places its period very near two years. To a 3-sigma uncertainty of 23.9 hours in closest approach time, the next Earth conjunction will be (you guessed it) early on 2011 Oct 17 UTC. Depending on how the statistics play out, perigee could be as low as 178,600 km on that occasion. I imagine interest in reacquiring (2009 TM8) will be high during the summer/fall of 2011. -Dan
    Here is a link to the original ATIG #26 email file.
  • ATIG_025__2011_10_05 [October 5, 2011] International Astronautical Congress (IAC) 2011
    ATIG Members- The attached paper is being presented by NASA Associate Administrator Bill Gerstenmaier at this year’s IAC on October 7. Feel free to feed comments or questions to me. -Dan
    [IAC_2011_A5.4.7_RevD.pdf, 12 pages, 637 KB]
    Here is a link to the original ATIG #25 email file.
  • ATIG_024__2011_10_02 [October 2, 2011] *Responsible* Human Space Flight
    ATIG Members- The attached PDF is an op-ed draft inspired by NASA’s recent heavy lift Space Launch System announcement. Assuming this system to loft humans beyond LEO goes operational, we’ll have enough capability to be dangerous. The issue I’m trying to confront is: will we provide the responsible strategies, infrastructure, and trained personnel to go with this capability? I’m hoping this piece will soon be published in Space News. Thanks to those among you who have helped me pull this draft together. -Dan
    [ResponsibleHSFr1.pdf, 2 pages, 85 KB]
    Here is a link to the original ATIG #24 email file.
  • ATIG_023__2011_09_25 [September 25, 2011] GRAIL to the Moon
    ATIG Members- The attached PDF is a draft article on GRAIL’s trans-lunar coast and lunar orbit insertion trajectory intended for publication in AIAA-Houston Section’s November-December newsletter. Any feedback is welcome at any time, but my newsletter deadline is September 30. -Dan
    [GRAILtoMoonR1.pdf, 6 pages, 504 KB]
    Here is a link to the original ATIG #23 email file.
  • ATIG_022__2011_09_18 [September 18, 2011] Dawn Reaches HAMO
    ATIG Members- Just before 2011 Sep 1.0 UTC, Dawn began lowering its orbit altitude about (4) Vesta from 2700 km to 680 km. At the same time, Dawn rotated the descending node of its orbit on Vesta’s equator from 15 deg west of local solar noon about 15 deg westward toward Vesta’s sunrise terminator. Thanks to a September 15 posting on JPL’s Horizons server, this transition from Dawn’s survey orbit to its high altitude mapping orbit (HAMO) about Vesta is chronicled by the attached plot. This plot’s plane very nearly coincides with that of the HAMO. If the transition went according to the posted plan, HAMO was reached around 2011 Sep 17.6 UTC. -Dan
    [DawnVsVestaR5.gif, 267 KB]
    Here is a link to the original ATIG #22 email file.
  • ATIG_021__2011_08_10 [August 10, 2011] NEO Accessibility Paper
    ATIG Members- The attached bookmarked PDF is a paper I presented to the AAS/AIAA Astrodynamics Specialist conference last week. It will also be the subject of a presentation I’m scheduled to make at the June 26 Trajectory Think Tank (T3) seminar. Any feedback on the paper is welcome, including any questions or topics you’d like addressed at T3. This is definitely ongoing research! -Dan
    [AAS 11-449r3.pdf, 20 pages, 1.4 MB]
    Here is a link to the original ATIG #21 email file.
  • ATIG_020__2011_07_19 [July 19, 2011] Dawn Arrival at Main Belt Asteroid (4) Vesta
    ATIG Members- I‘ve never looked into traj ops for a spacecraft with solar electric propulsion (SEP), so I resolved to get a taste of them with Dawn’s historic arrival in orbit about Vesta this month. Talk about TIG slip capability! Even terminal approach burns with durations measured in weeks can easily be postponed by days with no ill effects. The attached draft article is to be published in the August issue of the AIAA Houston Section’s newsletter. Be in touch if you run across any errors or glaring omissions, as these can probably be corrected over the next week or so. I remain unconvinced that electric propulsion, even with a nuclear reactor as its power source, is advisable on a crewed spacecraft. However, this technology could play important supporting roles in HSF, particularly when those roles are not time-critical. -Dan
    [DawnVestaArrivalR1.pdf, 4 pages, 258 KB]
    Here is a link to the original ATIG #20 email file.
  • ATIG_019__2011_06_02 [June 2, 2011] The Red Baron Scenario
    ATIG Members- I‘ve agreed to author a series of informal articles dealing with astrodynamics themes for publication by the AIAA-Houston Section in its Horizons newsletter. Newsletter editor Douglas Yazell has graciously permitted me share the initial draft of my first article, titled “The Red Baron Scenario In An Interplanetary Context”, with all of you. Kindly review the attached PDF and forward any comments or corrections to me in the next week, if possible. Many thanks! -Dan
    [RedBaronScenarioR1.pdf, 6 pages, 387 KB]
    Here is a link to the original ATIG #19 email file.
  • ATIG_018__2011_03_17 [March 17, 2011] Mercury Orbit Insertion (MOI)
    ATIG Members- After nearly 7 years of interplanetary cruise, the MESSENGER robotic probe will become the first artifact to orbit Mercury at 8 PM CDT tonight (http://messenger.jhuapl.edu/mer_orbit.html). A heliocentric trajectory plot showing the end of interplanetary cruise is attached, along with a Mercury-centered plot showing terminal approach, MOI, and the first orbit of Mercury (actually Orbit 0 and the first half of Orbit 1 the way JHU-APL controllers reckon it). -Dan
    [MOImerc.gif, 150 KB, MOIhelio.gif, 148 IB]
    Here is a link to the original ATIG #18 email file.
  • ATIG_017__2011_01_10 [January 10, 2011] Accessible NEOs Paper
    ATIG Members- Happy 2011! According to my records, a preliminary draft of the attached paper was uploaded on December 7, 2009 to those of you who were ATIG members then. Since that initial upload, the paper benefitted from multiple peer review cycles and was published in the November-December 2010 issue of AIAA’s Journal of Spacecraft and Rockets (Vol. 47, No. 6). The published version may be accessed via www.aiaa.org. Unfortunately, the JSR baseline suffers from errata I couldn’t correct and absence of color due to lack of funding. The attached version attempts to correct those deficiencies and may be freely distributed without charge to recipients. I hope you find use for this research from the heady days of the 2009 Augustine Commission and inception of The Flexible Path. The paper is already starting to show its age, but that’s what being “on the cutting edge” is all about. 😉 -Dan
    [AccessibleAsteroidsR0.pdf, 17 pages, 1 MB]
    Here is a link to the original ATIG #17 email file.
  • ATIG_016__2010_10_14 [October 14, 2010] Propellant Depot Locations
    ATIG Members- Many of you familiar with my lunar surface rendezvous (LSR) rants would likely count me as a propellant depot advocate. Last month, I appeared on The Space Show (read summaries and hear recordings at http://www.thespaceshow.org/ for Sep/7/2010 and Sep/23/2010) twice to qualify that advocacy. These appearances led to a more formal and technical propellant depot presentation at GSFC/Harley Thronson’s Future In-Space Operations (FISO) telecon on October 13. I think many of you will find the attached FISO charts of interest. As always, I welcome feedback or questions, including any invitations to present this material at a time and place we coordinate. Enjoy! -Dan
    [PropDepotChartsFISOr1.pdf, 16 pages, 419 KB]
    Here is a link to the original ATIG #16 email file.
  • ATIG_015__2010_10_02 [October 2, 2010] “Mars Approach and Deimos Rendezvous” on YouTube
    ATIG Members- As some of you know, I attended my first International Space Development Conference (ISDC) in Chicago this May. At the ISDC, my colleague Jim Logan and I presented a 3-hour seminar on interplanetary travel with foreseeable technology. One of the high points in the seminar was a video of Mars approach and rendezvous with its outer moon Deimos. The video’s premier at the ISDC had no audio track, as I simply narrated what was being rendered. As a follow-on action, Jim and I have packaged the video for YouTube posting with 2 minutes of shameless self-promotion, followed by 6.5 minutes explaining how Mars can be explored by humans using Deimos as a convenient observation post and habitat. If your PC is HD-capable, I recommend selecting 720pHD and full-screen from controls at the lower right of YouTube’s video player. The URL is http://www.youtube.com/watch?v=X10GAqA4Ky4. Enjoy! -Dan
    Here is a link to the original ATIG #15 email file.
  • ATIG_014__2010_08_13 [August 13, 2010] An Opinion On Initial Steps Toward NEO Exploration
    ATIG Members- During June and July, I had the honor of ghost writing an editorial on where U.S. priorities should lie with respect to near-Earth object (NEO) exploration in the near term. I learned a lot from some very smart people and wanted to share that knowledge with those of you who haven’t seen the result. The attached PDF is shamelessly scanned from August 2’s issue of Space News. I invite any feedback on it you’d care to send my way. Until our next seminar, keep ’em flying! -Dan
    [AsPublishedOpEd.pdf, 2 pages, 314 KB]
    Here is a link to the original ATIG #14 email file.
  • ATIG_013__2009_12_07 [December 7, 2009] Accessible Near Earth Objects (NEOs)
    ATIG Members- Attached is a draft paper documenting how prospective NEO human exploration opportunities were identified and assessed under auspices of the Augustine Commission earlier this year. This PDF is bookmarked to facilitate navigation, and I welcome questions or comments regarding it. Please refrain from further distribution of the PDF because it will soon be submitted to a peer-reviewed journal. Those desiring a PDF copy who aren’t on ATIG distribution may be referred to me for an upload. A Happy 2010 to all of you! -Dan
    [NEOmissionSurveyR2.pdf, 15 pages, 1.1 MB]
    Here is a link to the original ATIG #13 email file.
  • ATIG_012__2009_10_21 [October 21, 2009] Asteroid (2009 TM8)
    ATIG Members- Last Friday evening Oct 16 CDT, yet another asteroid briefly came closer to Earth than the Moon. Flyby geometry for the interloper, provisionally designated (2009 TM8), is illustrated in the attached geocentric plot. With the Moon and Sun roughly to the left of Earth in the geocentric plot, (2009 TM8) crossed Earth’s heliocentric orbit ahead of our path around the Sun. Earth flyby geometry therefore caused (2009 TM8) to lose some heliocentric orbit energy. This is apparent from the heliocentric plot spanning 2009 and 2010. Note the shift to lower aphelion as the (2009 TM8) plot begins and ends. As of October 18, JPL’s orbit solution for (2009 TM8) contained 36 observations over a 2-day arc. By October 20, 48 observations had been processed over the same arc. Because (2009 TM8)’s Earth departure was toward the Sun, I’m speculating the observation arc won’t be extended later in time very much. The only significant improvement in the orbit solution would come from a serendipitous pre-discovery observation. Nevertheless, current knowledge of (2009 TM8)’s post-flyby heliocentric orbit places its period very near two years. To a 3-sigma uncertainty of 23.9 hours in closest approach time, the next Earth conjunction will be (you guessed it) early on 2011 Oct 17 UTC. Depending on how the statistics play out, perigee could be as low as 178,600 km on that occasion. I imagine interest in reacquiring (2009 TM8) will be high during the summer/fall of 2011. -Dan
    [(2009 TM8)helio.gif, 71 KB, (2009 TM8)geo.gif, 61 KB]
    Here is a link to the original ATIG #12 email file.
  • ATIG_011__2009_09_17 [September 17, 2009] MESSENGER Mercury Flyby #3
    ATIG Members- This is coming to you a bit early, but I thought I’d get trajectory plots of MESSENGER’s third Mercury flyby in your email before Cathy Osgood retires from 50 years of service to the US space program and her address is deactivated. Closest approach to Mercury will be just before 5 PM CDT on September 29. This mission’s final gravity assist sets the stage for MESSENGER to achieve orbit about Mercury on March 18, 2011. Launch was August 3, 2004. -Dan
    [Mrec3helio.gif, 66 KB, Merc3merc.gif, 62 KB]
    Here is a link to the original ATIG #11 email file.
  • ATIG_010__2009_09_05 [September 5, 2009] LCROSS Status
    ATIG Members- Many of you are already familiar with the Lunar CRater Observation and Sensing Satellite (LCROSS) mission to impact a permanently shaded “cold trap” near the Moon’s south pole and detect any substantial water deposits there. http://www.nasa.gov/mission_pages/LCROSS/main/index.html. Two weeks ago, LCROSS declared a spacecraft emergency after attitude control malfunctions expended nearly all the spacecraft’s propulsion margin while out of contact with NASA’s Deep Space Network (DSN). This incident occurred at one of the mission’s worst possible intervals, when LCROSS was far south of the celestial equator and virtually invisible from two of the three DSN sites (only the site near Canberra, Australia is in the southern hemisphere). After some heroics by operations personnel, LCROSS stood down from emergency status on September 3. Just before the Labor Day weekend, dedicated JPL personnel (in the FDO/TOPO tradition) posted an LCROSS ephemeris update to their Horizons website reflecting tracking into September 3. Coasting from a terminal Horizons state 431 sec beforehand, I infer a lunar impact on October 9 at 11:26:05 UTC near 67.9 deg S; 58.5 deg W. If I coast from a September 4.0 Horizons state, impact is 11:27:26 UTC near 69.6 deg S; 55.8 deg W. From these two coasts, it appears there are no future LCROSS maneuvers in Horizons, but it won’t take much propulsion to hit the target impact point when it’s selected on or about September 10. I’m frankly amazed the attitude “control” impulses 2 weeks ago didn’t introduce more impact trajectory error. Attached are a couple trajectory plots from the September 4.0 coast. Feel free to share these with colleagues if you wish. -Dan
    [Sep3ancGeo.gif, 78 KB, Sep3ancSel.gif, 64 KB]
    Here is a link to the original ATIG #10 email file.
  • ATIG_009__2009_09_01 [September 1, 2009] Human Max Altitude Record
    ATIG Members- If you happened to view the Air & Space Museum’s Apollo 11 Fortieth Anniversary Gala (televised on NASA TV this past July 20), you’ll recall remarks by MC Dr. Neil deGrasse Tyson regarding Apollo 13’s crew holding the subject record. Having already published research on reconstructing Apollo 13’s trajectory, I resolved to verify this claim and possibly refine the record’s value/pedigree. Results of this work are attached as a bookmarked PDF file. Please note this is a preliminary draft of a paper intended for your review and comment prior to formal publication. I therefore request you not redistribute this file. If others are interested in a copy, please refer them to me, and I’ll supply them with the latest. I hope you find this paper useful, and thanks for any corrections or other comments you care to send my way. -Dan
    [ApolloMaxH.pdf, 11 pages, 1.2 MB]
    Here is a link to the original ATIG #09 email file.
  • ATIG_008__2009_06_20 [June 20, 2009] LCROSS Trajectory Plots
    ATIG Members- Although NASA posts all kinds of detailed as-tracked trajectory data for Shuttle and ISS (I used to help do that job in my former FDO life), there’s the usual dearth of this information available following Thursday’s LRO/LCROSS launch. All I could find was a planned LCROSS trajectory posted on JPL Horizons. Although these planned data assume an on-time Thursday launch 20-min earlier than the actual event, the attached plots should be reasonably accurate for purposes of gross situational awareness. In the LCROSSgeo Earth-centered plot, lunar encounter is evident from the trajectory’s S-turn as the nearly stationary LCROSS and attached Centaur upper stage are overrun by the Moon at a geocentric speed 5 times greater. The resulting lunar gravity assist flings LCROSS/Centaur into a longer period Earth orbit at greater ecliptic inclination from which lunar impact will be targeted for 2009 October 9. The LCROSS lunar gravity assist is plotted at greater detail in the LCROSSsel attachment. Perspective for this plot is orthogonal to the Moon-centered trajectory’s plane from a direction very close to Earth’s. As indicated by the Moon’s shading, its geocentric phase is just past new. According to the USNO, new Moon is 2009 June 22 @ 19:35 UTC. If LCROSS is able to operate its visible and IR cameras during closest approach to the Moon, some spectacular imagery of rugged terrain at low solar elevation directly below the spacecraft would be obtained. These images might include the eventual impact site near the Moon’s south pole. -Dan
    [LCROSSsel.gif, 63 KB, LCROSSgeo.gif, 61 KB]
    Here is a link to the original ATIG #08 email file.
  • ATIG_007__2009_06_04 [June 4, 2009] Lunar Surface Rendezvous (LSR) Lunch ‘n Learn
    ATIG Members- Per the attached flyer, AIAA Houston Section’s Astrodynamics Technical Committee (ATC) will host a Lunch ‘n Learn seminar next Friday, June 12, at noon in B16/R111. I will lead a 45-minute discussion of my LSR research. Anticipating many questions/comments on this work, the room has been reserved until 1:30 PM. The last time I circulated my LSR white paper among all ATIG members, it was Revision 2 last November 20. The latest Revision 6 is attached for your reference as the Augustine Commission’s tenure begins. It commences with a single-page executive summary and is bookmarked to facilitate navigation. I’m indebted to the ATC’s chair, Al Jackson, for coordinating this seminar at a very timely juncture and hope schedules will permit many of you to attend. -Dan
    [LSRvirtuesR6.pdf, 14 pages, 339 KB, LSRflyerLnL.pdf, 1 page, 301 KB]
    Here is a link to the original ATIG #07 email file.
  • ATIG_006__2009_04_13 [April 13, 2009] Twenty Years & Counting…
    ATIG Members- As a confirmed NEOphyte, I would be remiss in not noting it’s twenty years today until potentially hazardous asteroid (99942) Apophis misses Earth by ~31800 km on Friday the 13th of April 2029. Depending largely on what happens then, there’s something like a 1-in-40000 chance of Apophis Earth impact on (Roman) Easter Sunday April 13, 2036. This is all unabashed promotion for my two presentations at the AIAA Houston Section’s Annual Technical Symposium on May 15, 2009. Facsimile abstracts for the two presentations are attached. Hope to see you at Gilruth Center for these presentations (assuming they’re accepted). -Dan
    [AdamoApophisAbstract.pdf, 1 page, 72 KB, AdamoLSRabstract.pdf, 1 page, 65 KB]
    Here is a link to the original ATIG #06 email file.
  • ATIG_005__2009_03_20 [March 20, 2009] Venus Pix
    ATIG Members- As illustrated in the attached GIF’s J2000.0 ecliptic plane plot of Earth and Venus motion about the Sun, a line of sight from Earth to the Sun is in the +X direction today, and Spring is here. This line also passes very close to Venus, making it dangerous for me to continue taking daytime images of our sister planet without frying my telescope’s optics. Venus will “lap” Earth (in the heliocentric sense) on March 24, an event known as inferior conjunction. The attached JPEG is a montage of 4 daytime Venus images obtained at an effective magnification of 62x during the GIF plot’s time span. Each image is cropped to 615 px in horizontal dimension and 397 px in vertical dimension to maintain a consistent scale illustrating progressively smaller Venus geocentric distance during the sequence. To state image scale in more absolute terms, Venus apparent angular diameter in the March 20 image is 58 arc-sec, approaching resolution capability of the unaided human eye. Of course, don’t even think about looking for Venus in the daytime with a line of sight this close to the Sun! Each image in the JPEG is oriented with celestial north upward to demonstrate rotation of the Venus morning terminator as its phase evolves from “quarter Moon” to crescent. The “horns” of this crescent clearly become biased in a northerly direction as inferior conjunction approaches. This is because Venus lies more than 3 deg north of the ecliptic plane on March 20. Currently, the orbit of Venus has a descending node on the ecliptic at a heliocentric longitude occupied by Earth in early June each year. In 2012, Venus descending nodal passage will occur near enough to inferior conjunction to produce a transit of Venus across the Sun as observed from Earth. If the attached files won’t download in your copy of Outlook, they will in NASA WebMail. -Dan
    [Earth+Venus.gif, 53KB, Venus2009.jpg, 161 KB]
    Here is a link to the original ATIG #05 email file.
  • ATIG_004__2009_03_13 [March 13, 2009] Curious Cassini Conundrum
    ATIG Members- In reading March 12’s issue of Cassini Significant Events, a weekly JPL PAO newsletter, I ran across the following riddle.

    Thursday, March 5 (DOY 064):

    How is it that at one moment Cassini can be found nearly at apoapsis, the farthest point from Saturn in an orbit, and within a day, be at periapsis, the closest point to Saturn in an orbit, when its orbital period is around 16 days? Well, it is happening at the end of March this year. On DOY-86, Mar. 27, the Titan 51 targeted flyby will occur. Just a few hours later, apoapsis and the start of orbit #107 would have occurred. However, because of the gravitational influence of Titan during the flyby, Cassini’s orbit is modified such that apoapsis on the new Saturn centered orbit occurs prior to the Titan encounter, on an orbit different from the one Cassini actually flew. For orbit 107, on DOY-87, Mar. 28, Cassini is now at the closest point to Saturn in that orbit. The above scenario is unique in the history of the project and will not occur again before the end of the extended mission. The fact that Cassini’s orbit about Saturn is very nearly circular at this time is what enables this rather curious sequence of events.

    Saturn-centered geometry pertaining to Titan-51’s 180-deg apsidal shift is illustrated in the attached CassiniVsSaturn GIF. The viewpoint for this trajectory plot is nearly normal with respect to Cassini orbit planes before and after the Titan-51 flyby. Note Saturn’s north pole, just visible from this perspective and emerging from nearly 15 Earth years of winter darkness, is pointed downward. The attached CassiniVsTitan trajectory plot is also viewed from nearly normal to the Cassini plane of motion, but in a Titan-centered reference frame. In this case, Titan’s south pole is visible and pointed downward. Periapsis height for this flyby is planned at +960 km. If Outlook won’t download these GIFs, remember that NASA WebMail will. -Dan
    [CassiniVsTitan.gif, 62 KB, CassiniVsSaturn.gif, 74 KB]
    Here is a link to the original ATIG #04 email file.

  • ATIG_003__2009_02_23 [February 23, 2009] LSR Mission Design
    ATIG Members- Happy 2009! Following through on my latest research indicating lunar surface rendezvous (LSR) is a practical Moon exploration architecture with two Ares V launches, I’ve spent the last couple months generating and documenting an illustrative mission design. Notionally staged in 2019 to coincide with Apollo 11’s fiftieth anniversary, this particular LSR mission targets a landing near Aristarchus Crater where planetary science interest is high. Crew lunar surface operations are deliberately planned for one week duration in order to pose nearly worst-case geometry to lunar orbit rendezvous and Earth return due to 90 deg of lunar rotation/revolution of a mid-latitude location. As documented in the attached mission design paper (packaged as a bookmarked PDF), nominal LSR mission design is free from geometric performance “humps” from event timing. In addition to the nominal LSR mission design, the paper documents associated trans-lunar, low lunar orbit, and no-LOI abort options. It concludes with a deep space crew rescue mission design. Both nominal and anomalous trajectories are demonstrated to be in accord with vehicle performance specifications developed in the original LSR white paper, indicating this architecture is operationally viable and robust. Your feedback on the attached paper is requested. As always, I’m willing to discuss this research in our usual seminar format at any venue to which I have access. As a further demonstration of LSR capability, I next intend to plan an LSR landing at a lunar surface location nearly inaccessible to current 1.5-launch architecture due to performance limitations. I posit this mission’s nominal LSR performance demands will differ very little from those of the nominal Aristarchus mission. In this manner, LSR’s capability to fully and robustly satisfy the “land anywhere; leave anytime” US Space Exploration Policy requirement will be further demonstrated. Suggestions for this “performance-challenged” mission’s landing site coordinates are certainly welcome. In lieu of any better input, I’ve tentatively selected the center of a performance “hole” in CxP temporal availability contour plots (reference pp. 20 – 23 of [7] in the attached paper) at 55 deg S lat; 25 deg W lon. As Sir Arthur would have it, this location is ~90 km NW of the NW rim of Clavius Crater. -Dan
    [LSRin2019.pdf, 34 pages, 2 MB]
    Here is a link to the original ATIG #03 email file.
  • ATIG_002__2008_11_08 [November 8, 2008] LSR, Anyone? [LSR: Lunar Surface Rendezvous]
    ATIG Members- Many of you have known me to make occasional quixotic forays into the realm of lunar exploration architecture.  Retirement from conventional employment only affords more opportunities for such adventures. Since the 2005 Exploration System Architecture Study (ESAS) put us on the current “1.5-launch” architecture path, a series of Ares I performance setbacks have imposed compensating Ares V performance upgrades.  In terms of single-launch Ares V payload injection capacity into a trans-lunar trajectory (no Ares I payload assist via LEO rendezvous), September 2008 performance data indicate a 15% increase with respect to an ESAS-vintage baseline. The attached white paper proposes a means by which enhanced Ares V performance may be used to implement a Lunar Surface Rendezvous (LSR) “2.0-launch” architecture.  Multiple vulnerabilities in the current 1.5-launch architecture are mitigated using the proposed LSR mission profile, and the paper documents these in some detail. As stated in the paper’s Introduction, the attached bookmarked PDF may be freely distributed provided it is not altered. As always, your feedback on the paper’s content is invited, and I would be honored to discuss it at any venue to which I’m provided access. -Dan
    [Link: LSRvirtuesR2.pdf, 236 KB, 10 pages.]
    Here is a link to the original ATIG #02 email file.
  • ATIG_001__2008_08_18 [August 18, 2008] Rosetta’s Flyby Of Asteroid 2867 Steins
    ATIG Members- Per the attached trajectory plots of ESA’s Rosetta spacecraft, its first asteroid encounter is being targeted for September 5, when an approach to 800 km is planned.  Per the Rosetta web page at URL http://www.esa.int/SPECIALS/Rosetta/index.html, the targeting process is an active one.  A period of optical navigation being conducted from August 4 to September 4 is being used to refine Steins’ orbit uncertainty from 100 km to 2 km in the Rosetta B-plane (plane orthogonal to Rosetta’s Steins-relative velocity vector).  Highest resolution in images obtained during the Steins flyby is expected to approach 10 m. -Dan Adamo
    [Links: RosettaSteins.gif (57 KB), RosettaSteinsHelio.gif (63 KB)]
    Here is a link to the original ATIG #01 email file.

Members of the AIAA Houston Section astrodynamics technical committee

  • Dr. Albert Allen Jackson IV, Chair
    • Associate Fellow, AIAA
    • Fellow, British Interplanetary Society
    • Senior Member, American Astronautical Society
    • NASA civil servant: 5 years in the Apollo program, Lunar Module Simulator instructor, Abort Guidance System and Primary Guidance and Navigation system. MacDonnell Douglas, Computer Science Corporation, Lockheed: Flight planning software, Orbit debris and Engineering Simulation, 40 years.
    • Douglas Yazell volunteered in 2015 to create an oral history document here about the career of Dr. Jackson, to be placed here and on the AIAA Houston Section history technical committee web page.
    • Dr. Jackson was a team member on a ten-year software project which won second place in 2014 in a NASA competition. Of all the NASA awards in his decades-long career in the NASA/JSC community, this is the only one that included a cash prize.
    • March 2015: Dr. Jackson penciled in a Lunch-and-Learn presentation about Traversable Wormholes with himself as the speaker. The movie Interstellar is still talked about in the press and is still in theaters, so that movie might create some interest in this subject.
  • Douglas Yazell, Honeywell 1981-2011, Horizons newsletter editor 2011-2014
  • Dr. Tim Crain, Intuitive Machines

We are always looking for new professional members. Contact information is on the organization chart.

Charter

To provide a forum for exchange of ideas and information regarding the state of the art and the future of astrodynamics. To stimulate education, professional development, and accomplishment by fostering communication and by providing resources.

Goals

  • Recruit members for the technical committee and AIAA
  • Recruit one technical committee member from each ‘astrodynamics’ company in the NASA/JSC community
  • Encourage lectures from government, industry, and universities
  • Monitor and contribute to the mirror committee on the national level
  • Organize lunch-and-learn sessions in the the Houston Clear Lake area (one to four per year)
  • Focus on the technical challenges of the next 3-5 years
  • Meet in person three to four times per year, sometimes with national committee
  • Interact with other AIAA technical committees (including AIAA Houston Section Annual Technical Symposium [ATS] in May of each year), other professional societies, and universities
  • Survey tools and techniques
  • Contribute articles to AIAA Houston Section Horizons newsletter
  • Initiate and review reports on astrodynamics of missions to Mars, Lagrange points, asteroids and cislunar space

Presentations by Dr. Albert Allen Jackson IV

Extreme SETI (1 MB, PDF, a PowerPoint presentation, 20 pages)

Here is the same presentation (PDF) with an audio transcript added using Post-It notes in the PDF. Download this and open it with  the free Adobe Reader application in order to see the Post-It notes. The image of Arthur C. Clarke is updated here on the first slide, since the aspect ratio was distorted in the original presentation.

September 19, 2014, at the 100 Year Starship (100YSS) public symposium, G. R. Brown Convention Center, Houston Texas USA, 3:30 PM

Search for Extraterrestrial Intelligence (SETI) is so well-known that it is barely worthwhile to define it here. See the related newsletter article starting on page 13 of the March / April 2014 issue (36 pages, 5 MB PDF) of Horizons, Detecting Starships. The original title of that  article was Extreme SETI, but the Horizons Editor decided to avoid undefined acronyms, following the Yahoo style guide. So Horizons, the newsletter of AIAA Houston Section, was first to publish this Extreme SETI subject as written by Dr. Albert Allen Jackson IV.

The above 20-page presentation is not an AIAA presentation, but we have permission from Dr. Jackson to place his presentation file here.

In work September 25, 2014: I (Douglas Yazell) have an iPhone 5 audio recording of the above 15-minute presentation, missing only the first few words. I volunteer to transcribe it and place that PDF file here. In fact, instead of a PDF file, I can probably add that text to the 20 pages above using Adobe Acrobat Post-In Notes. Putting the audio file here would be useful, too, but it is a long audio file that includes a presentation by another speaker, so editing of that audio file would be required.

Lunch-N-Learns

  • [Event date (past): Friday: February 12, 2016]:
    • Time: Noon to 1:00 PM
    • Place: NASA/JSC Gilruth Center Lone Star room (Maximum capacity: 54 people) Six people per round table.
    • Speaker (invited & confirmed): Art Dula (link to the Arthur M. Dula Wikipedia article)
    • Subject: Space Mineral Resources, a Global Assessment, Challenges and Opportunities, Art Dula, Editor, a book published in September of 2015 (see the image below)
    • Details:
      • Link to an EventBrite page for this event
      • Link to the event page at www.aiaahouston.org
      • Link to the one-page publicity flyer
      • Either the EventBrite or the event page link was used to sign up in advance
      • Walk-ins were welcome
      • Optional lunch meal if ordered and paid for in advance online (Red River BBQ)
      • Lunch cost was published on those two web pages
      • Free event for those who preferred to attend without buying lunch
      • Link to book cover image and editor list
  • December 5, 2014
    Economics of Asteroid Mining
    Shen Ge, Bachelor’s Degrees of Science, Georgia Tech University, Aerospace Engineering & Physics; Master’s Degree of Science, Texas A&M University, Aerospace Engineering.
    Location: NASA Johnson Space Center Gilruth Center Coronado Room
    Attendance: 16
    Link to one slide (one chart) of images for and from this event
    PresentationPDF
  • June 7, 2010
    Exploring Near-Earth Objects (NEOs) with Human and Robotic Systems
    Daniel R. Adamo, astrodynamics consultant, Houston, Texas 77059, and Rob Landis, NASA
    Presentation: PDF
  • April 26, 2010
    How to Build Cost-Optimized Interstellar Beacons (and How to Search for Them)
    James N. Benford, Ph.D., Microwave Sciences, Inc.
    Publicity Flier: PDF
  • November 20, 2009
    Apollo 12, the 40th Anniversary, a Panel Discussion
    Panelists: Emil Schiesser (MPAD flight planner), Francis E. “Frank” Hughes (simulator trainer), and Floyd Bennett (flight controller)
    Publicity Flier: DOC
  • November 13, 2009
    The Japanese Hayabusa Spacecraft with Sample Return from Asteroid Itokawa
    Dr. Paul Abell, Lunar and Planetary Institute, Houston Texas
    Publicity Flier: DOC
  • June 12, 2009
    A Lunar Surface Rendezvous Architecture Proposal
    Daniel R. Adamo, astrodynamics consultant, Houston Texas 77059
    Publicity Flier: PDF
  • December 19, 2008
    Apollo 8: The 40th Anniversary
    Panelists: Hal Beck, Rod Rose, Marty Jeness, Ken Young, John Llewellyn, Dr. Glynn Lunney, Dr. Christopher Kraft, and Emil Schiesser
    Moderator: Marianne Dyson
    Publicity Flier: PDF
  • March 10, 2008
    Mars Exploration Rovers Spirit & Opportunity
    Dr. Mark Adler, Chief Mission Concept Architect, Jet Propulsion Laboratory
    Publicity Flier: PDF
  • February 21, 2008
    Tour of Ad Astra Rocket Company
    Hosted by Jared Squire
    Publicity Flier: PDF
  • January 11, 2008
    Space and Astronomy: Decade by Decade
    Marianne Dyson, author and former NASA flight controller,
    Publicity Flier: DOC
  • December 7, 2007
    Report on Lunar Exploration Analysis Group (LEAG) Workshop and American Astronautical Society National Meeting
    Dr. Larry Friesen
    Publicity Flier: PDF
  • November 2, 2007
    Apollo 13 Trajectory Reconstruction
    Daniel R. Adamo
    Publicity Flier: PDF
  • September 28, 2007
    Werner Von Braun’s Long Road to Mars: A Story Within a Story
    Dr. Albert Jackson / ESCG
    Publicity Flier: PDF
    Presentation: PDF
  • June 16, 2005
    Aerospace on the FASTRAC: Student Built Satellites at the University of Texas
    Dr. E. Glenn Lightsey / The University of Texas at Austin
    Flier: PDF 
  • May 19, 2005
    Hierarchical Navigation Algorithms in Support of Mars Exploration
    Robert H. Bishop / The University of Texas at Austin
    Flier: DOC
    Presentation: PDF
  • September 17, 2004
    Trajectory Optimization from Euler to Lawden to Today
    Christopher D’Souza / The Charles Stark Draper Laboratory
    Flier: PDF
    Presentation: PDF
  • March 24, 2004 
    Jules Verne and ISS, European Space Agency’s Automated Transfer Vehicle (ATV) First Rendezvous and Docking for a European Spacecraft
    Brian Rishikof / Odyssey Space Research
    Flier: PDF
    Presentation: PPT, 3.25 MB 
  • December 19, 2003
    StarNav-1 Experiment on STS-107
    Dr. Thomas C. Pollock / Texas A&M University
    Flier: PDF
  • November 14, 2003
    Spacecraft Fuel-Optimal Maneuvers, Apollo to Shuttle Return-to-Flight
    Rob Hall / Draper Laboratory

Resources

News

News Articles Published Now and Then


[2017 01 02] Published here January 2, 2017. Adamo Astrodynamics Archive Copied to Our Web Page. (It is a pleasure to connect Snoopy and the Red Baron to this subject.) Here is a link to the PDF version of the JPEG image below. [Update January 7, 2017: Please click here to see the the news about the updated URL for the AIAA copy of this archive. The news article below (JPEG and PDF versions) does not need updating, since www.aiaahouston.org/astrodynamics_technical_committee/#ATIG will lead to www.aiaahouston.org/adamo_astrodynamics.

Above: Adamo Astrodynamics Archive Copied to Our Web Page. (Click to zoom.)

Above: Adamo Astrodynamics Archive Copied to Our Web Page. (Click to zoom.)

[2016 08 14] August 14, 2016 A Green Flash at Sunrise Dan Adamo (adamod at earthlink dot net) emailed a sunrise green flash photo to one of us. He is now retired and living in Oregon instead of the Houston area in Texas, and the photo shows Mount Hood. He allowed us to publish the photo here, along with that part of his email note: “With the Sun moving south to about +20.5 deg declination, it was time to take shots of Mt. Hood sunrises from my location this week.  I’ve attached one capturing yet another green flash as the first rays of sunlight reached me over the mountain’s north slope on July 20.  During less than 2 seconds on this occasion, my visual impressions were of intense blue fading to green and yellow.  It’s an amazing sight, and it fell 13 months plus a day before 2 minutes of total solar eclipse will favor my abode.  Hope the weather’s as nice… -Dan”. Link: IMG_1961.jpg, 354 KB.

[2015 03 05] March 5, 2015 100 YEAR STARSHIP ESTABLISHES EU HUB IN BRUSSELS TO ADVANCE SPACE, SCIENCE AND TECHNOLOGY INITIATIVES WITH EUROPEAN PARTNERS

Read the press release using the 100YSS press page link and the press release date (March 5, 2015).

[2015 02 26] February 26, 2015 French National Center for Space Studies (CNES) at the First International Academy of Astronautics (IAA) Climate Change Conference

[This CNES press release (see this link) explains that climate change is an aerospace subject and explains that climate change is an astronautics subject. In fact, it mentions that of 50 variables used to define climate, 26 of them can be measured only from space.]

[Jean-Yves Le Gall, President of the French National Center for Space Studies (CNES), opened the first conference on climate change and disaster management, organized by the International Academy of Astronautics (IAA) and the International Institute of Space Law (IISL), which was held from February 26 to 28 in Kovalam, Kerala, India.]

This conference, co-organized by the IAA, IISL, and the KSCSTE (Kerala State Council for Science, Technology and Environment), focuses mainly on the many contributions of space in the understanding of climate change. Specifically, of 50 variables used to define the climate, 26 can only be measured from space, demonstrating the importance of this area to assess the changing climate.

The IAA is a non-governmental organization recognized by the United Nations, which brings together 1,200 international experts in astronautics from about 75 countries. Its objectives are to promote the development of astronautics for peaceful purposes and to honor those who are distinguished in astronautics. It promotes international cooperation for the advancement of aerospace sciences.

Invited to deliver the keynote address, Jean-Yves Le Gall, Chairman of CNES, first emphasized the historic challenge facing the space to preserve the future of the planet: “Space agencies can not answer all questions but without space agencies, nothing will be done. ” In this context, he has said that, “global Earth observations were indispensable to understand climate change and to make the most appropriate responses.”

Then he emphasized, “the important role of the international program GCOS (Global Climate Observing System)”, recalling that, “Europe, and specifically France, were actors in the forefront in climate observation.” In this area, the programs named Copernicus, Jason, SWOT and Merlin are of major importance. Cooperation between India and France is already very productive, notably with missions Megha-Tropiques and Saral-AltiKa.

“The future Conference of Parties 21 (COP 21, a meeting of the IPCC, the International Panel on Climate Change, associated with the United Nations) to be held in Paris in December, the importance of the IAA and its voice in the world, and international cooperation in space are elements and events that must converge to a general awareness for the protection of the planet through the regular collection and continuous analysis of data from space technology,“ he said. He concluded by stressing the need to mobilize all actors because, quoting the Secretary General of the United Nations, “There is no Plan B because there is no planet B.”

Translation from French to English by Douglas Yazell, with excellent help from http://translate.google.com.

[End of AIAA Houston Section astrodynamics technical committee web page, July 27, 2016]

Recent Posts

Erich Klein to Receive AIAA 2017 Otto C. Winzen Lifetime Achievement Award

Congratulations, Mr. Klein! We are proud of your accomplishments as a member of the Houston Section and are very pleased to hear of your winning of the 2017 Otto C. Winzen Lifetime Achievement Award.

Please look for an invitation in the coming months to also be recognized at our annual awards dinner in June.

See the award notification letter (PDF))

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