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STS-125/400 Single Pad option progress - aim to protect Ares I-X
by
Chris Bergin
on 19 Jan, 2009 20:29
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#1
by
marsavian
on 19 Jan, 2009 20:41
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From a timeline standpoint, the difference between Single Pad and Dual Pad options - according to the original presentation - changes the ability to launch Endeavour on a rescue from three days from LON call-up (Dual Pads) to 15 days after LON call up (Single Pad).
12 days difference is far too long, the idea should be abandoned. I am all for flying I-X even if just to collect the data for future posterity/use if it's canned but this is just too dangerous an idea especially if an MMOD impact happens very late. Ultimate Safety first and last should be the creed with the fragile Shuttle.
p.s. nice thorough article as always.
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#2
by
psloss
on 19 Jan, 2009 21:04
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12 days difference is far too long, the idea should be abandoned. I am all for flying I-X even if just to collect the data for future posterity/use if it's canned but this is just too dangerous an idea especially if an MMOD impact happens very late. Ultimate Safety first and last should be the creed with the fragile Shuttle.
I believe John Shannon has been saying for a while now that the choice isn't about safety so much as about schedule trades between the different HSF programs (Shuttle, ISS, Constellation). Since the time the dual pad option was originally selected, more of the repair capabilities were demonstrated in-flight. Even when they were executing the dual pad plan last fall, IIRC he said in the 125 preflight briefings that the STS-400 LON capability was largely for a STS-107-type launch incident rather than for something discovered during late inspection.
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#3
by
Shuttle Man
on 19 Jan, 2009 21:06
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Agreed, and that will be why they rejected the idea originally. I suspect that will be trimmed slightly, but for a contingency unlikely ever to be required, even that timeline is workable. Remember, the chances of this being needed are very slim, and Constellation's pressure for Ares I-X is great.
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#4
by
marsavian
on 19 Jan, 2009 21:18
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12 days difference is far too long, the idea should be abandoned. I am all for flying I-X even if just to collect the data for future posterity/use if it's canned but this is just too dangerous an idea especially if an MMOD impact happens very late. Ultimate Safety first and last should be the creed with the fragile Shuttle.
I believe John Shannon has been saying for a while now that the choice isn't about safety so much as about schedule trades between the different HSF programs (Shuttle, ISS, Constellation). Since the time the dual pad option was originally selected, more of the repair capabilities were demonstrated in-flight. Even when they were executing the dual pad plan last fall, IIRC he said in the 125 preflight briefings that the STS-400 LON capability was largely for a STS-107-type launch incident rather than for something discovered during late inspection.
What if the Shuttle is hit by a sizeable MMOD that punctures life support systems. The 9 day difference between the two options could mean the difference between life and death. How could anyone forgive themselves if this scenario came about and they knew they could have been saved with another flight plan, it would be like Columbia all over again.
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#5
by
marsavian
on 19 Jan, 2009 21:20
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Agreed, and that will be why they rejected the idea originally. I suspect that will be trimmed slightly, but for a contingency unlikely ever to be required, even that timeline is workable. Remember, the chances of this being needed are very slim, and Constellation's pressure for Ares I-X is great.
Who cares, I-X is not a long pole item. If Cx cannot survive due to a 3 month I-X delay it was not built on any solid foundations in the first place.
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#6
by
ChrisGebhardt
on 19 Jan, 2009 21:26
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Agreed, and that will be why they rejected the idea originally. I suspect that will be trimmed slightly, but for a contingency unlikely ever to be required, even that timeline is workable. Remember, the chances of this being needed are very slim, and Constellation's pressure for Ares I-X is great.
Agreed psloss and Shuttle Man. My question, however, is on the techincal side of the STS-400 vehicle processing. The presentation and article say that Endeavour will undergo pad processing up to hyper loading. My question: why can't they load the hypergols at the pad and then roll back to the VAB? IIRC, Atlantis' hypergols were removed back in October because of the possibility of destacking and return to the OPF, not because there is some rule precluding the presence of hypergols in the VAB. If the hypergols were loaded before the 400 vehicle rolled back to the VAB, wouldn't that save them some time on the pad in the unlikely event that 400 actually needed to launch?
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#7
by
ChrisGebhardt
on 19 Jan, 2009 21:31
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Agreed, and that will be why they rejected the idea originally. I suspect that will be trimmed slightly, but for a contingency unlikely ever to be required, even that timeline is workable. Remember, the chances of this being needed are very slim, and Constellation's pressure for Ares I-X is great.
Who cares, I-X is not a long pole item. If Cx cannot survive due to a 3 month I-X delay it was not built on any solid foundations in the first place.
You're missing the point of what psloss and Shuttle Man are trying to tell you. It is all about give and take. If the Space Shuttle Program engineers come to the conclusion that we can safely launch HST and (if needed) 400 from the same pad because of all the on-orbit repair capabilities we now have, then they will take that option and turn over Pad-B to Cx. If it is determined that we can't do that safely, and Pad-B is required for 400, than that's exactly what we'll do and Cx will wait because it is necessary for HST crew's safety in the highly unlikely event that 400 is needed.
And I-X is very much a long pole item for Cx given all the data it will accumulate as Cx heads into further critical design reviews. If I-X was not a long pole item we would not be flying it.
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#8
by
marsavian
on 19 Jan, 2009 21:35
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J2-X is and has always been the Ares I long pole item followed by Orion. The on-orbit repair capability is for known TPS damage not unknown MMOD damage. Look at the MMOD hits recently, luckily in uncritical areas, die are being thrown every time up there.
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#9
by
psloss
on 19 Jan, 2009 21:35
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What if the Shuttle is hit by a sizeable MMOD that punctures life support systems. The 9 day difference between the two options could mean the difference between life and death. How could anyone forgive themselves if this scenario came about and they knew they could have been saved with another flight plan, it would be like Columbia all over again.
If the MMOD only compromises the life support systems in a non-catastrophic way, they jettison HST and land as soon as they can -- assuming the leak rate is slow enough. But if it's a large leak and they can't re-enter, there's not enough time to get
any rescue vehicle up there fast enough.
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#10
by
psloss
on 19 Jan, 2009 21:40
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My question: why can't they load the hypergols at the pad and then roll back to the VAB? IIRC, Atlantis' hypergols were removed back in October because of the possibility of destacking and return to the OPF, not because there is some rule precluding the presence of hypergols in the VAB. If the hypergols were loaded before the 400 vehicle rolled back to the VAB, wouldn't that save them some time on the pad in the unlikely event that 400 actually needed to launch?
Don't think that's right, then -- they would load hypers on the 400 vehicle during the first stay at the pad. The second stay would be very similar to what they did with the 115 vehicle after disconnecting it to partially roll back for the tropical storm. Pad validations, connecting ordnance, countdown preps, pressurizing OMS/RCS, aft closeouts, countdown and launch.
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#11
by
marsavian
on 19 Jan, 2009 21:44
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What if the Shuttle is hit by a sizeable MMOD that punctures life support systems. The 9 day difference between the two options could mean the difference between life and death. How could anyone forgive themselves if this scenario came about and they knew they could have been saved with another flight plan, it would be like Columbia all over again.
If the MMOD only compromises the life support systems in a non-catastrophic way, they jettison HST and land as soon as they can -- assuming the leak rate is slow enough. But if it's a large leak and they can't re-enter, there's not enough time to get any rescue vehicle up there fast enough.
What if there is irreparable damage to the TPS too ? There are so many unexpected bad things that could potentially happen all at once, think Apollo 13 for example. Without the safety of the ISS nearby, and a rescue Shuttle nearly 2 weeks away, this plan is Russian Roulette IMO. Again I can't believe this option is being seriously considered.
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#12
by
ChrisGebhardt
on 19 Jan, 2009 21:53
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What if the Shuttle is hit by a sizeable MMOD that punctures life support systems. The 9 day difference between the two options could mean the difference between life and death. How could anyone forgive themselves if this scenario came about and they knew they could have been saved with another flight plan, it would be like Columbia all over again.
If the MMOD only compromises the life support systems in a non-catastrophic way, they jettison HST and land as soon as they can -- assuming the leak rate is slow enough. But if it's a large leak and they can't re-enter, there's not enough time to get any rescue vehicle up there fast enough.
What if there is irreparable damage to the TPS too ?
Then the LON Shuttle WILL BE launched!!!! Once again (and this is the last statement I'm making on this discussion), if there is any type of unrepairable damage the LON shuttle will be launched in time to rescuse the crew -- no matter what day of the mission the damage is detected! Like psloss said earlier, if the damage was so critical from MMOD that it compromised life support capabilities to the point that the crew couldn't LAND Atlantis in time, we could not get 400 there fast enough even if it was launched from Pad-B. Therefore, your question about irrepairable damage as well is irrelevant because it would sadly be a LOC scenario regardless of LON ability. The bottom line is this: any type of survivable damage incurred during launch or while on orbit would result in the launch of the LON vehicle in time to rescue the HST crew.
Furthermore, John Shannon and Wayne Hale have said SEVERAL times that LON capability is for Columbia style damage and, sometimes, minor MMOD strikes. Not extreme MMOD cases. This means TPS damage! Therefore, 400 will serve its purpose no matter which Pad it's stationed on.
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#13
by
AnalogMan
on 19 Jan, 2009 21:55
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My question: why can't they load the hypergols at the pad and then roll back to the VAB? IIRC, Atlantis' hypergols were removed back in October because of the possibility of destacking and return to the OPF, not because there is some rule precluding the presence of hypergols in the VAB. If the hypergols were loaded before the 400 vehicle rolled back to the VAB, wouldn't that save them some time on the pad in the unlikely event that 400 actually needed to launch?
Don't think that's right, then -- they would load hypers on the 400 vehicle during the first stay at the pad. The second stay would be very similar to what they did with the 115 vehicle after disconnecting it to partially roll back for the tropical storm. Pad validations, connecting ordnance, countdown preps, pressurizing OMS/RCS, aft closeouts, countdown and launch.
Looking at the L2 presentation, the hypergols
are loaded on the LON at the first pad visit, and rolled back to the VAB in that condition.
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#14
by
ChrisGebhardt
on 19 Jan, 2009 21:58
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My question: why can't they load the hypergols at the pad and then roll back to the VAB? IIRC, Atlantis' hypergols were removed back in October because of the possibility of destacking and return to the OPF, not because there is some rule precluding the presence of hypergols in the VAB. If the hypergols were loaded before the 400 vehicle rolled back to the VAB, wouldn't that save them some time on the pad in the unlikely event that 400 actually needed to launch?
Don't think that's right, then -- they would load hypers on the 400 vehicle during the first stay at the pad. The second stay would be very similar to what they did with the 115 vehicle after disconnecting it to partially roll back for the tropical storm. Pad validations, connecting ordnance, countdown preps, pressurizing OMS/RCS, aft closeouts, countdown and launch.
Looking at the L2 presentation, the hypergols are loaded on the LON at the first pad visit, and rolled back to the VAB in that condition.
Ah... thanks.
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#15
by
marsavian
on 19 Jan, 2009 21:59
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What if the Shuttle is hit by a sizeable MMOD that punctures life support systems. The 9 day difference between the two options could mean the difference between life and death. How could anyone forgive themselves if this scenario came about and they knew they could have been saved with another flight plan, it would be like Columbia all over again.
If the MMOD only compromises the life support systems in a non-catastrophic way, they jettison HST and land as soon as they can -- assuming the leak rate is slow enough. But if it's a large leak and they can't re-enter, there's not enough time to get any rescue vehicle up there fast enough.
What if there is irreparable damage to the TPS too ?
Then the LON Shuttle WILL BE launched!!!! Once again (and this is the last statement I'm making on this discussion), if there is any type of unrepairable damage the LON shuttle will be launched in time to rescuse the crew -- no matter what day of the mission the damage is detected! Like psloss said earlier, if the damage was so critical from MMOD that it compromised life support capabilities to the point that the crew couldn't LAND Atlantis in time, we could not get 400 there fast enough even if it was launched from Pad-B. The bottom line is this: any type of survivable damage incurred during launch or while on orbit would result in the launch of the LON vehicle in time to rescue the HST crew.
Your 'bottom line' cannot be said with absolute authority to be true in every possible outcome. No-one is thinking outside the box here. There is no ISS safe shelter here guys, that's the crucial difference. The crew may not survive anyway in really bad conditions but there are ranges of possibilities whose span covers days (different leak rates allied with totally hosed TPS) in which a different plan could make the difference.
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#16
by
psloss
on 19 Jan, 2009 22:17
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Your 'bottom line' cannot be said with absolute authority to be true in every possible outcome. No-one is thinking outside the box here. There is no ISS safe shelter here guys, that's the crucial difference. The crew may not survive anyway in really bad conditions but there are ranges of possibilities whose span covers days (different leak rates allied with totally hosed TPS) in which a different plan could make the difference.
A crew and vehicle won't survive every possible outcome during ISS missions, either. You can postulate leaks with entry-critical damage at times on ISS missions when there's no safe haven either.
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#17
by
marsavian
on 19 Jan, 2009 22:25
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Your 'bottom line' cannot be said with absolute authority to be true in every possible outcome. No-one is thinking outside the box here. There is no ISS safe shelter here guys, that's the crucial difference. The crew may not survive anyway in really bad conditions but there are ranges of possibilities whose span covers days (different leak rates allied with totally hosed TPS) in which a different plan could make the difference.
A crew and vehicle won't survive every possible outcome during ISS missions, either. You can postulate leaks with entry-critical damage at times on ISS missions when there's no safe haven either.
Indeed, but why limit ourselves for something that is not as important as maximising the life chances of the Astronauts. If the World is forced to watch these guys die and it is known the Agency could have made a difference if not for the trivial sake of testing the World's Biggest Firework early, it would never be forgiven. 3 strikes and you are out !
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#18
by
Chris Bergin
on 19 Jan, 2009 22:43
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My question: why can't they load the hypergols at the pad and then roll back to the VAB? IIRC, Atlantis' hypergols were removed back in October because of the possibility of destacking and return to the OPF, not because there is some rule precluding the presence of hypergols in the VAB. If the hypergols were loaded before the 400 vehicle rolled back to the VAB, wouldn't that save them some time on the pad in the unlikely event that 400 actually needed to launch?
Don't think that's right, then -- they would load hypers on the 400 vehicle during the first stay at the pad. The second stay would be very similar to what they did with the 115 vehicle after disconnecting it to partially roll back for the tropical storm. Pad validations, connecting ordnance, countdown preps, pressurizing OMS/RCS, aft closeouts, countdown and launch.
Looking at the L2 presentation, the hypergols are loaded on the LON at the first pad visit, and rolled back to the VAB in that condition.
It says to proceed through half of pad flow and stop at Hyper load. Doesn't that mean prior to Hyper load, rather than after? If there's another indication noted that I missed, then it means changing one word in the article, but it's still important.
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#19
by
psloss
on 19 Jan, 2009 22:45
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Indeed, but why limit ourselves for something that is not as important as maximising the life chances of the Astronauts. If the World is forced to watch these guys die and it is known the Agency could have made a difference if not for the trivial sake of testing the World's Biggest Firework early, it would never be forgiven. 3 strikes and you are out !
What evidence do you have that NASA's stakeholders would view it that way? If I-X is just a fireworks display, it should be canceled for THAT reason.