Zoomer30 - 22/11/2007 9:54 PMOk I have a "did they ever consider doing this test "question. I know that they at one point were really thinking about using one of the test flights of the Columbia as a RTLS abort test flight. Bascially fly to SRB sep, then simulate some "issue" and swtich to RTLS abort mode and do it. That was quickly dropped since that abort mode is very risky and was not worth the risk for a somewhat low chance of being needed option (ATO, TAA and AOA are much more likely).Anyway, did they ever consider using Enterprise to do a ALT type test at the KSC runway? I guess they was not much NEED to do one since no landings where planned their till 83 or so (Solar Max mission was the first I think, even though it had been planned for the flight before).Did they ever think to do that just to get a feel for a landing at the ultra long but ultral narrow KSC strip??
Zoomer30 - 24/11/2007 9:54 PMThe RTLS would be needed in only a few very specific situations. I think if an engine failed during the first 2 mins they would not have enough thrust to pull off an RTLS at that point, I think it would end up being a ditching abort.
An engine failure very late in the SRB burn would probably be the only time I can see. Its a very low probability of being needed in my mind, since so many things need to happen just right to be able to get back. I think its only about the first 3mins or so one can be attempted.
Jorge - 24/11/2007 11:58 PMIn practice, an RTLS would not be used for an engine failure after the first TAL boundary. However, in the event of a systems failure that requires earliest possible landing, such as a cabin leak or loss of both Freon loops, a 3-engine RTLS may be performed up to Negative Return.
dbhyslop - 24/11/2007 11:54 PMQuoteJorge - 24/11/2007 11:58 PMIn practice, an RTLS would not be used for an engine failure after the first TAL boundary. However, in the event of a systems failure that requires earliest possible landing, such as a cabin leak or loss of both Freon loops, a 3-engine RTLS may be performed up to Negative Return.It is interesting to learn this. I recall reading in another thread that RTLS is considered risky, particularly separating from an ET that may have sloshing propellants. Would they really choose the RTLS abort mode over the TAL in the event of a cabin leak, given the fact that the crew are in pressure suits?
I assume these risks have already been quantified to determine the abort criteria in the flight rules, etc?
spaceshuttle - 25/11/2007 11:38 PMExternal Tank No. 1 was never flown. Does anyone know what it was used for?
Yes. The rules require RTLS to be performed for:1) Impending loss of all APU/hydraulic capability2) Failure of a forward windshield or side hatch thermal (outer) window pane3) Cabin leak with dP/dt > 0.15 psia/min4) Impending loss of all O2 or H2 cryo5) Loss of two Freon loops6) Loss of any two main DC electrical buses (due to loss of ET door closure capability)
MB123 - 26/11/2007 4:12 AMLoss of power on both DC buses, thats an interesting one. I thought that astronauts were trained, and have been since STS-1, to perform a spacewalk to close ET doors in this event. Does anyone have any dot-points as to why the spacewalk is (apparently) a less attractive option than the RTLS abort in this case?mb
MB123 - 26/11/2007 4:12 AMLoss of power on both DC buses, thats an interesting one.mb
rdale - 27/11/2007 11:21 PMOnly at a press conference, when some reporter asks "is this the most complex mission to date" and the answer is completely up to the asker. If you think adding a European module is historic, then 122 is a biggie. If you think that fixing a solar array is a milestone, then 120 is too...