A Proposed Launch Performance Standard

User-Agent: Microsoft-Entourage/12.36.0.130206 Date: Sun, 07 Dec 2014 17:06:58 -0700 Subject: A Proposed Launch Performance Standard From: Daniel Adamo Message-ID: Thread-Topic: A Proposed Launch Performance Standard Thread-Index: AdASg0O58PHWvU3FBkahH1PyMbTGyA== Mime-version: 1.0 Content-type: multipart/alternative; boundary="B_3552816906_4453529" > This message is in MIME format. Since your mail reader does not understand this format, some or all of this message may not be legible. --B_3552816906_4453529 Content-type: text/plain; charset="US-ASCII" Content-transfer-encoding: 7bit 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 --B_3552816906_4453529 Content-type: text/html; charset="US-ASCII" Content-transfer-encoding: quoted-printable A Proposed Launch Performance Standard ATIG Members-

Many of you who correspond with me on "rocket science" matters ar= e familiar with my rant on absence of a performance standard for launch vehi= cles such that "apples versus apples" comparisons may be made. &nb= sp;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 compa= red to other launch vehicles? And what is meant by "power" a= nyway? Thrust at liftoff is likely a poor metric for what really count= s: initial mass delivered to low Earth orbit by a single launch (IMLEO). &nb= sp;So, here's my proposed standard for an IMLEO-based launch performance met= ric.

First, some relevant background is warranted. Forty-two years ago tod= ay, on 7 Dec 1972, a Saturn V launched the Apollo XVII mission from KSC LC 3= 9A (28.608 deg N Lat, 80.604 deg W Lon, -32.0 m Alt) at an azimuth of 91.5 d= eg E of N. Some 11.9 min after launch, insertion into a 166.7 km altit= ude circular orbit (reckoned with respect to an Earth radius of 6378.2 km) w= as achieved. Inclination of this orbit was 28.526 deg. See Ap= ollo: 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 w= ith their launch vehicle (whether operational or under design), and report t= heir IMLEO values via email along with the launch vehicle configuration simu= lated. These IMLEO results will be cited with the proposed standard at= http://spaceenterpriseinstit= ute.org/, facilitating an "apples versus apples" performance c= omparison between launch vehicles.

I'd be very interested in any commentary regarding the proposed standard. &= nbsp;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 S= huttle launch into the Apollo XVII orbit. Just how much Orbiter mass c= an be inserted into this orbit without incurring a low level MPS cutoff? &nb= sp;If I have to use OMS-2 to circularize at 166.7 km, that propellant will c= ome out of the IMLEO I report. But I will report "useless" I= MLEO mass like the Orbiter's wings.

-Dan --B_3552816906_4453529--