THrust From United States of America, joined Sep 2003, 2673 posts, RR: 11 Posted (8 months 3 weeks 2 days 20 hours ago) and read 5517 times:
Hi there. I had a question regarding the external tank. I know there were possible plans to reuse them in earth orbit that never materialized. Could the space shuttle actually have burned into earth orbit with the external tank still attached to it without any modifications, and a full payload in its cargo bay? And if so, would its total LEO payload have surpassed that of the Saturn V?
By several of my calculations, it shows that it would indeed have surpassed the Saturn V. The earlier standard tanks weighed 77,000 lbs dry. Combined with the shuttle's 240,000 pound payload capacity, this would have resulted in a payload to earth orbit of greater than 310,000 pounds, more than Apollo 15's payload. Even with the super-lightweight tanks, this still would've tied the Saturn V.
Now, my calculations are my calculations. I'm trying to get input from others on this forum regarding this question. I was once under the impression the shuttle was not as powerful as the Saturn V. Now I'm not so sure.
vikkyvik From United States of America, joined Jul 2003, 8220 posts, RR: 28 Reply 1, posted (8 months 3 weeks 2 days 16 hours ago) and read 5449 times:
AIRLINERS.NET CREW PHOTO SCREENER
Quoting THrust (Thread starter): Combined with the shuttle's 240,000 pound payload capacity
I think you quoted the wrong figure. The orbiter's Gross Liftoff Weight appears to be 240,000 lbs, while the Max Payload appears to be ~55,000 lbs.
"Two and a Half Men" was filmed in front of a live ostrich.
KC135TopBoom From United States of America, joined Jan 2005, 11708 posts, RR: 52 Reply 3, posted (8 months 3 weeks 2 days 4 hours ago) and read 5294 times:
Quoting THrust (Thread starter): would its total LEO payload have surpassed that of the Saturn V?
Quoting vikkyvik (Reply 1): The orbiter's Gross Liftoff Weight appears to be 240,000 lbs, while the Max Payload appears to be ~55,000 lbs.
Quoting THrust (Reply 2): i'm talking about total weight injected into space.
The Saturn V rocket still holds the records for weight it can send to LEO and to TLI. To LEO (any orbit with an altitude BELOW 2,000 km, or about 1,200 miles) the S-V can lift 260,000 lbs. In other words it could lift the MGW of the fully loaded Shuttle, and then some.
To TLI (Trans Lunar Injection), the S-V could lift 100,000 lbs. In other words, the S-V can lift almost twice the weight the Shuttle can put into Low Earth Orbit, but send it onto Trans Lunar Injection (which is the point after at least one complete orbit of the Earth, so speed can build up, that you begin to leave the Earth Orbit on your way to the Moon).
There has never been a rocket as capable or as reliable as the Saturn V. It 'flew' 11 times (13 if you count the Saturn INT-21), and was successful every time. It did have one partial launch failure, Apollo-6, the rocket experienced severe Pogo Oscillations, due to the attachments of the F-1 engines, then after the 3rd stage was exhausted and jettisoned, the 2nd stage lost 2 of its 5 J-2 engines, but it still made it into a 200 mile high orbit.
Some have suggested the Apollo-13 mission was also an S-V failure, but it was not. The O2 tank explosion aboard the A-13 SM was some 56 hours after the launch, and some 200,000 miles in altitude. This was well after the S-V did its job of the launch and insertion into TLI.
Apollo 13 is often mentioned as a possible S-V "failure" because there was a centre engine cutout on the second stage due to pogo-ing, in addition to the famous CM issue.
KC135TopBoom From United States of America, joined Jan 2005, 11708 posts, RR: 52 Reply 5, posted (8 months 3 weeks 2 days ago) and read 5206 times:
I have never heard of a PO event with the A-13 mission, nor a J-2 engine shutdown. But even if this did happen, it would be considered a 'partial failure' as they still got to TLI.
Do you have a link to the event? I'm not saying it didn't happen, just I have not heard of it happening, other than the A-6 mission.
ZANL188 From United States of America, joined Oct 2006, 3248 posts, RR: 0 Reply 6, posted (8 months 3 weeks 1 day 23 hours ago) and read 5190 times:
Quoting KC135TopBoom (Reply 5): Do you have a link to the event? I'm not saying it didn't happen, just I have not heard of it happening, other than the A-6 mission.
Early center engine shutdown on the Apollo 13 S-II is a well known event. Check your own sources. No way it would be considered a failure, glitch yes, failure no.
Quoting KC135TopBoom (Reply 3): It did have one partial launch failure, Apollo-6, the rocket experienced severe Pogo Oscillations, due to the attachments of the F-1 engines, then after the 3rd stage was exhausted and jettisoned, the 2nd stage lost 2 of its 5 J-2 engines, but it still made it into a 200 mile high orbit.
Your sequence is all wrong... You can't have an exhausted and jettisoned 3rd stage BEFORE 2 engines shutdown early on the 2nd stage. Apollo 6 would have been aborted had there been a crew aboard. I'd call it a successful failure though because many things were learned and there wasn't much if any delay caused by Apollo 6.
Quoting KC135TopBoom (Reply 3): To TLI (Trans Lunar Injection), the S-V could lift 100,000 lbs. In other words, the S-V can lift almost twice the weight the Shuttle can put into Low Earth Orbit, but send it onto Trans Lunar Injection (which is the point after at least one complete orbit of the Earth, so speed can build up, that you begin to leave the Earth Orbit on your way to the Moon).
TLI is not a chance to let "speed build up". TLI is when the 3rd stage is reignited to send the spacecraft to the moon.
Legal considerations provided by: Dewey, Cheatum, and Howe
checksixx From United States of America, joined Mar 2005, 996 posts, RR: 0 Reply 7, posted (8 months 3 weeks 1 day 15 hours ago) and read 5096 times:
Quoting THrust (Thread starter): Hi there. I had a question regarding the external tank. I know there were possible plans to reuse them in earth orbit that never materialized. Could the space shuttle actually have burned into earth orbit with the external tank still attached to it without any modifications, and a full payload in its cargo bay?
I'm not aware of any plans, EVER, to reuse the external tanks. They were designed into the program from the start to be one time use. The space shuttle 'burned' into earth orbit EVERY time with the tank attached until MECO.
stealthz From Australia, joined Feb 2005, 5431 posts, RR: 49 Reply 8, posted (8 months 3 weeks 1 day 14 hours ago) and read 5087 times:
Quoting checksixx (Reply 7): I'm not aware of any plans, EVER, to reuse the external tanks.
I recall articles from the early days of the shuttle program that had concept proposals and artwork for "space stations" assembled from numbers of external tanks, an expansion of the Skylab concept perhaps.
I don't know if these were ever solid engineering proposals or Marketing spin to bolster the concept of STS as an economical and perhaps even a commercially viable concept.
If your camera sends text messages, that could explain why your photos are rubbish!
vzlet From United States of America, joined Mar 2004, 820 posts, RR: 0 Reply 9, posted (8 months 3 weeks 1 day 11 hours ago) and read 5046 times:
Quoting checksixx (Reply 7): The space shuttle 'burned' into earth orbit EVERY time with the tank attached until MECO.
Think about that for a second. If a shuttle (and the still-attached external tank) had orbital velocity at MECO, then the tank itself did too. That obviously wasn't the case. The orbiter required additional velocity from OMS firing(s) to reach orbit.
"That's so stupid! If they're so secret, why are they out where everyone can see them?" - my kid
ZANL188 From United States of America, joined Oct 2006, 3248 posts, RR: 0 Reply 10, posted (8 months 3 weeks 1 day 11 hours ago) and read 5031 times:
Quoting checksixx (Reply 7): I'm not aware of any plans, EVER, to reuse the external tanks.
Quoting stealthz (Reply 8): I recall articles from the early days of the shuttle program that had concept proposals and artwork for "space stations" assembled from numbers of external tanks, an expansion of the Skylab concept perhaps.
I don't know if these were ever solid engineering proposals or Marketing spin to bolster the concept of STS as an economical and perhaps even a commercially viable concept.
NASA has/had plans for many missions it never actually flew.
Quoting vzlet (Reply 9): Think about that for a second. If a shuttle (and the still-attached external tank) had orbital velocity at MECO, then the tank itself did too. That obviously wasn't the case. The orbiter required additional velocity from OMS firing(s) to reach orbit.
The ETs were jettisoned from shuttle with almost all the energy needed to go into orbit. They just needed to circularize the orbit and they'd have been in orbit. Further the tanks usually had leftover propellant, add a small engine and voila it's in orbit. Or they may have been able to use a propulsive "vent" (adds velocity) instead of a destructive "vent" (causes tumbling, aids reentry). Not sure if a propulsive vent would have added the required delta-V
Quoting KC135TopBoom (Reply 3): There has never been a rocket as capable or as reliable as the Saturn V. It 'flew' 11 times (13 if you count the Saturn INT-21), and was successful every time.
Bullhockey. There are a number of launch vehicles that have had a string of successes that long before (or between) failures. Had S-V flown more it would've had a failure. Saturn V was like Concorde in this respect... all it would've taken is one accident to go from first to worst, statistically speaking...
Legal considerations provided by: Dewey, Cheatum, and Howe
connies4ever From Canada, joined Feb 2006, 3857 posts, RR: 13 Reply 11, posted (8 months 3 weeks 1 day 11 hours ago) and read 5026 times:
Quoting KC135TopBoom (Reply 3): Some have suggested the Apollo-13 mission was also an S-V failure, but it was not. The O2 tank explosion aboard the A-13 SM was some 56 hours after the launch, and some 200,000 miles in altitude. This was well after the S-V did its job of the launch and insertion into TLI.
Agreed the centre engine S-II shutdown on Apollo 13 was not a failure but a problem. But it could have been much worse.
Quoting checksixx (Reply 7): Quoting THrust (Thread starter):
Hi there. I had a question regarding the external tank. I know there were possible plans to reuse them in earth orbit that never materialized. Could the space shuttle actually have burned into earth orbit with the external tank still attached to it without any modifications, and a full payload in its cargo bay?
I'm not aware of any plans, EVER, to reuse the external tanks. They were designed into the program from the start to be one time use. The space shuttle 'burned' into earth orbit EVERY time with the tank attached until MECO.
Yah, agreed. I think perhaps OP has confused SS ET re-use with early Apollo Application (as it was then called) studies that looked at re-using the S-IVB stage in orbit . In the end of course the whole S-IVB was replaced with a fully-kitted laboratory.
nomadd22 From United States of America, joined Feb 2008, 1561 posts, RR: 0 Reply 13, posted (8 months 3 weeks 1 day 2 hours ago) and read 4901 times:
Quoting ZANL188 (Reply 10): Bullhockey. There are a number of launch vehicles that have had a string of successes that long before (or between) failures. Had S-V flown more it would've had a failure. Saturn V was like Concorde in this respect... all it would've taken is one accident to go from first to worst, statistically speaking...
Atlas V is at 32 launches without a failure. One Centaur quit a little soon, but the payload still made it to it's intended orbit.
checksixx From United States of America, joined Mar 2005, 996 posts, RR: 0 Reply 14, posted (8 months 3 weeks 17 hours ago) and read 4785 times:
Quoting vzlet (Reply 9): Quoting checksixx (Reply 7):
The space shuttle 'burned' into earth orbit EVERY time with the tank attached until MECO.
Think about that for a second. If a shuttle (and the still-attached external tank) had orbital velocity at MECO, then the tank itself did too. That obviously wasn't the case. The orbiter required additional velocity from OMS firing(s) to reach orbit.
Areopagus From United States of America, joined Sep 2001, 1357 posts, RR: 1 Reply 16, posted (8 months 3 weeks 5 hours ago) and read 4660 times:
The shuttle flew a profile that dumped the ET back into the atmosphere over the Indian Ocean, while the orbiter did an OMS burn to get the delta-V to achieve a stable orbit. But I recall reading, around the time of the first shuttle flight, that it would have been more efficient to use SSME/ET propulsion to get all the way to orbit. The problem with that would be to have a derelict ET in orbit with no control over where its remnants fell. They took a payload hit in order to put it down safely short of orbit. IIRC, the payload penalty was not just due to propellant usage, but also to the depressed trajectory needed to put the ET down in the ocean.
As vzlet & Areopagus correctly point out the tanks were never orbited.. so I'm wondering how your statement " The space shuttle 'burned' into earth orbit EVERY time with the tank attached until MECO" is accurate?
Just so everyone understands the shuttle was not in orbit at MECO & neither was the tank. Shuttle required a burn of the OMS engines, some minutes after MECO, to circularize the trajectory and put shuttle in orbit. Without the OMS burn shuttle would have flown a ballistic trajectory and reentered.
Legal considerations provided by: Dewey, Cheatum, and Howe
checksixx From United States of America, joined Mar 2005, 996 posts, RR: 0 Reply 18, posted (8 months 2 weeks 4 days 18 hours ago) and read 4403 times:
Again...thanks for any help you think you may be providing, but my statement was accurate. Keep wondering why my statement is accurate or go find out for yourself...its up to you.
ZANL188 From United States of America, joined Oct 2006, 3248 posts, RR: 0 Reply 19, posted (8 months 2 weeks 3 days 8 hours ago) and read 4285 times:
Quoting checksixx (Reply 18): Again...thanks for any help you think you may be providing, but my statement was accurate. Keep wondering why my statement is accurate or go find out for yourself...its up to you.
Your statement was inaccurate using the common and accepted vernacular for "in orbit".
Legal considerations provided by: Dewey, Cheatum, and Howe
eksath From United States of America, joined Aug 2004, 1140 posts, RR: 27 Reply 20, posted (8 months 2 weeks 3 days 2 hours ago) and read 4227 times:
AIRLINERS.NET CREW ARTICLE EDITOR
Quoting vzlet (Reply 9): The orbiter required additional velocity from OMS firing(s) to reach orbit.
Quoting ZANL188 (Reply 17): Without the OMS burn shuttle would have flown a ballistic trajectory and reentered.
Not necessarily. This internal debate i.e. OMS burn or not hit the public eye when Astronaut Mike Mullane wrote his biography in 2005. In it he goes to great lengths to describe the battle he had with John Young (chief astronaut who fought this). John Young's argument was to save it for latter use in the mission if needed. Eventually, Young lost and it became standard practice.
I am reciting from memory hence besides the debate, i don't remember the other details. I can always talk to guys about it as this was SOP after the first few years.
By the way, i highly recommend Mike's book: "Riding Rockets". John Young's image takes a dent in it though. I always liked Young though. He was very friendly and with his strong southern accent, it was easy to forget who he was.
EDIT: did some research (quick), OMS engines NOT used during nominal ascent until STS-90 (1998). I can look up the detailed data files for this mission to see the rationale however I probably wont get to it until Endeavour leaves KSC.
ZANL188 From United States of America, joined Oct 2006, 3248 posts, RR: 0 Reply 21, posted (8 months 2 weeks 3 days 1 hour ago) and read 4212 times:
Quoting eksath (Reply 20): Not necessarily. This internal debate i.e. OMS burn or not hit the public eye when Astronaut Mike Mullane wrote his biography in 2005. In it he goes to great lengths to describe the battle he had with John Young (chief astronaut who fought this). John Young's argument was to save it for latter use in the mission if needed. Eventually, Young lost and it became standard practice.
Mullane butted heads with Young on the OMS assist manuever which occured pre-MECO, not post.
JBirdAV8r From United States of America, joined Jun 2001, 4459 posts, RR: 22 Reply 22, posted (8 months 2 weeks 3 days ago) and read 4198 times:
Quoting checksixx (Reply 18): Again...thanks for any help you think you may be providing, but my statement was accurate. Keep wondering why my statement is accurate or go find out for yourself...its up to you.
What a petty game of semantics.
Sure it "goes into orbit." But with orbital parameters that take the perigee into the Earth's atmosphere, it's quite useless, isn't it?
THrust From United States of America, joined Sep 2003, 2673 posts, RR: 11 Reply 23, posted (8 months 2 weeks 2 days 21 hours ago) and read 4145 times:
The question remains....could the external tank have been counted as payload to LEO, since it was attached to the shuttle all the way to MECO? And if the external tank were counted, would the shuttle surpass the Saturn V in payload?
Getting the tank all the way to MECO doesn't buy you much - it's still going to reenter before it completes the first orbit. Are you willing to trade off mass from elsewhere in the system? If so then maybe a way could be found to give the tank the extra delta-v to insert it into orbit..
The answer to your question? It depends...
Legal considerations provided by: Dewey, Cheatum, and Howe
kalvado From United States of America, joined Feb 2006, 471 posts, RR: 0 Reply 25, posted (8 months 2 weeks 2 days 9 hours ago) and read 4097 times:
Quoting THrust (Reply 23): The question remains....could the external tank have been counted as payload to LEO,
Last stage of many rockets orbits Earth for a while after the satellite separation, and is not treated as a payload. Noone actually willing to pay for that part to stay in orbit, so it is not payload
PW100 From Netherlands, joined Jan 2002, 1983 posts, RR: 10 Reply 26, posted (8 months 1 week 3 days 9 hours ago) and read 3818 times:
I guess the (theoretical) question THrust really means is as follows: what would be the Shuttle's payload hit, if the ET was NOT detached from the Shuttle prior to the OMS burn. Or, how much mass would the total system have in orbit, including ET if it was not jettisoned?
Immigration officer: "What's the purpose of your visit to the USA?" Spotter: "Shooting airliners with my Canon!"
rwessel From United States of America, joined Jan 2007, 1989 posts, RR: 2 Reply 27, posted (8 months 1 week 2 days 20 hours ago) and read 3748 times:
Quoting PW100 (Reply 26): guess the (theoretical) question THrust really means is as follows: what would be the Shuttle's payload hit, if the ET was NOT detached from the Shuttle prior to the OMS burn. Or, how much mass would the total system have in orbit, including ET if it was not jettisoned?
The question is how much delta-V you need to circularize the orbit. 200ft/s is probably a reasonable estimate for a low-ish orbit. Taking a 60,000lb empty tank weight (this is probably low, because of residual propellants), and an OMS engine ISP of 316, you'd need about 1200lbs of additional OMS/RCS propellant (for reference, the system carries just under 48,000lbs of fuel).
The higher you wanted the orbit, and the more unvented propellant left on board the ET, the more you'll need.
kalvado From United States of America, joined Feb 2006, 471 posts, RR: 0 Reply 28, posted (8 months 1 week 2 days 6 hours ago) and read 3666 times:
Quoting PW100 (Reply 26): I guess the (theoretical) question THrust really means is as follows: what would be the Shuttle's payload hit, if the ET was NOT detached from the Shuttle prior to the OMS burn.
Shuttle carried around 22 tons of hypergolic fuel for the OMS and zero-fuel weight of orbiter was about 100 tons, let's call it 1/5 of dry weight.
External tank weight went down from 35 to 26.5 tons - so full trip fuel cost would be 7 to 5 tons.
Tank would not need deorbit burn, so total is a bit lower, but 3-5 tons of fuel/payload hit probably is about right.
Sponsor Message: 
From United States of America, joined Sep 2003, 2673 posts, 
From Falkland Islands, joined May 2007, 3596 posts, 
From Australia, joined Feb 2005, 5431 posts, 
From Canada, joined Feb 2006, 3857 posts, 
From Netherlands, joined Jan 2002, 1983 posts, 
Sponsor Message: 
Printer friendly format
