Talk:Space Shuttle abort modes

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[edit] Previous discussion without headers

Renamed to correct plural spelling. All of this material is an article split from Space Shuttle program. Joema 19:16, 31 January 2006 (UTC)

What is an "SSMEs"? (term used in article needs to be defined) 70.182.14.11 09:16, 9 April 2006 (UTC)

It is defined -- not only spelled out, but the first mention is a hotlink to the article on Space Shuttle Main Engine (SSME). SSME is also hotlinked an other subsequent references, but not every single one. Wikipedia standards say all subsequent refs should not be hotlinked. Readers need only look at the first reference to see what SSME stands for, or click on any hyperlinked SSME reference to see an entire article on the subject. Joema 12:18, 9 April 2006 (UTC)

The use of so many acronyms makes reading this article difficult. —The preceding unsigned comment was added by 82.43.205.161 (talk) 23:01:45, August 19, 2007 (UTC)

[edit] RTLS

The RTLS abort is somewhat more complicated than described in the article. During the abort the computers are continually calculating the amount of fuel that would remain and the trajectory achieved if the shuttle was to pitch round so the engines were facing along the direction of travel, and only when the pitch around will leave it with the right amount of fuel (i.e. not much) at the right point in the trajectory (i.e. close enough to the runway to glide to a landing) to drop the tank does it actually perform the maneuver to start decelerating.

Prior to that time the primary concern is burning off excess fuel, which it does by pitching so the engines are facing downwards and the engine thrust is not significantly affecting the velocity. That has the useful side-effect of increasing the shuttle's altitude and giving them more room to maneuver during the abort.

I'm sure I have a NASA document somewhere that explains it all in great detail. MarkGrant 02:10, 10 July 2006 (UTC)

[edit] Comparison to other escape crew capsules

The article originally had this paragraph: "Cabin/capsule ejection systems have a spotty success record, likely because of the complexity. This was one reason the F-111 and B-1 cabin ejection was changed to conventional ejection seats for later aircraft versions."

I believe the second sentence is incorrect so I removed it. First, I cannot find sources to say that the F-111 ever changed from cabin ejection to conventional ejection seats. Second, my sources say that the cabin ejection used in three of the four B-1A prototypes was changed to conventional ejection seats due to either concern over pyrotechnical complexity and/or over cost and weight issues. [1] [2]

I did leave the first sentence, because it may be -- at least partially -- true. The XB-70 had at least three major problems with its capsule ejection system when AV/2 crashed. Also, the B-1A prototype #2 crash had parachute problems which killed one of the three people on board. I have not researched the B-58 or F-111 to find out if they had a spotty record.

For more information, see the article Escape crew capsule --Pmurph5 09:10, 13 August 2006 (UTC)

You're correct about the FB-111 not changing to ejection seats; thanks for catching that. However the FB-111 cabin ejection system definitely had a spotty record, significantly worse than typical military ejection seats. One study showed of 50 ejections from FB-111s, 20% were killed in the process (Bowman, 1993, Aircrew Ejection Injury Analysis and Trauma Assessment Criteria). Another study showed about 30% of those who survived the FB-111 cabin ejections had fractured spinal vertebrae, likely from the landing impact associated with the ejected cabin (Hearon, BF, 1982, Mechanism of vertebral fracture in the F/FB-111 ejection experience, Aviation Space and Environmental Medicine). Joema 03:13, 15 August 2006 (UTC)

[edit] Merging TransOceanic Abort Landing

I have no problems whatsoever with this merge. Go for it. In fact, considering that TransOceanic Abort Landing contains nothing new compared to what's here already, I'd simply convert it to a redirect, and be done with it. SchuminWeb (Talk) 09:37, 23 October 2006 (UTC)

[edit] STS-51-F abort to orbit

This article currently contains contradicting statements:

There are four intact abort modes, only one of which has ever occurred.
and
Abort to Orbit (ATO) […] This occurred on mission STS-51-F, which then required replanning but was declared a success.
versus
A hydrogen fuel leak on STS-93 resulted in a lower orbit than anticipated, but was not considered an ATO; if the leak had been more severe, it may have necessitated an ATO, RTLS or TAL abort.

Furthermore, STS-51-F currently says:

The failed SSME resulted in an Abort To Orbit (ATO) trajectory, whereby the shuttle achieves a lower than planned orbital altitude.

So, was this an official ATO, or just a near-ATO situation that was instead saved by mission replanning? Do we have an official NASA statement or other reliable source for exactly what this situation is considered to be? ~ Jeff Q (talk) 01:02, 10 December 2006 (UTC)

Best I can find ATM is This, which lists, amongst other things, Shuttle aborts. Note that only 5 RSLS and 1 ATO are listed. --GW_SimulationsUser Page | Talk 01:16, 10 December 2006 (UTC)
There has been only one in-flight abort, the ATO on STS-51-F. None of the above wording specifically contradicts that, but it was somewhat poorly worded and ambiguous. I revised it to clarify. Let me know if it's still not adequate. Joema 14:12, 10 December 2006 (UTC)

[edit] Autonomous Orbiter Rapid Prototype

I removed this section is it is not an abort mode. In addition, calling the section Autonomous Orbiter Rapid Prototype is incorrect as this was the name of the project methodology used to come up with the remote control orbiter cable, hence, rapid prototype. The cable is now stored on the ISS and is not carried on each mission. All this and more is already included in the STS-3xx article. Cjosefy 14:44, 11 December 2006 (UTC)

[edit] ECAL

I removed the section claiming a list of "designated" East Coast Abort Landing sites. The cited document is a master's thesis on the possibility of landing at various airports; it is not a NASA policy or operations document. Furthermore, it only applies to high-inclination launches (space station), as an alternative to the TAL abort mode. "This thesis will explore the possibilities of safely landing the Orbiter at an East Coast airport..." (pg. 1-5). There is one mention of ECAL on the KSC website, with no details given. It's certainly interesting information that might be worth reworking (it's all there in the history), but it's completely unsubstantiated as a NASA procedure. --Jnik 15:57, 20 July 2007 (UTC)

Fair enough. --SarekOfVulcan 15:00, 24 July 2007 (UTC)

[edit] Contradiction

The RSLS abort section states that "The SRBs cannot be turned off once ignited, and afterwards the shuttle is committed to take off. No abort options exist from the ignition of the SRBs until their burnout 123 seconds later". This is incorrect, and contradicts the rest of the article (specifically the RTLS abort section). I fixed this, but Andy120290 (talk · contribs) reverted my edit. Because I can't be bothered to argue with him or start an edit war, I've added a {{fact}} tag, and a {{contradict}} notice at the top of the page. --GW_SimulationsUser Page | Talk 23:12, 19 October 2007 (UTC)

I have taken the addition of a cite that contradicts the aforementioned claim as admission that the claim is incorrect, and I have reverted to my previous revision, leaving the cite in place. --GW_SimulationsUser Page | Talk 11:23, 20 October 2007 (UTC)
Andy's change was correct. The original wording (which you restored) was wrong. The cited reference is very clear on this: "powered RTLS phase begins with the crew selection of the RTLS abort, which is done after solid rocket booster separation". This obviously means no in-flight abort options exist before that point. Indeed, RTLS is not even selected until after SRB separation. If you could be more specific about what points you think are contradicting, or exactly why you think Andy's wording is incorrect, that would help. Joema 12:39, 20 October 2007 (UTC)
Re-examining it, I would say this may actually just be a case of ambiguous wording, and either rewriting, or completely removing the statement may be the best way to deal with the situation. The aforementioned claim implies that a problem occuring before SRB sep would be unrecoverable. --GW_SimulationsUser Page | Talk 13:47, 20 October 2007 (UTC)
I don't see the ambiguity. Andy's wording: "No abort options exist from the ignition of the SRBs until their burnout 123 seconds later" means for that interval, there are no abort options. You can't do an abort during that period. It doesn't say or imply anything else. By contrast the current wording is clearly wrong: "After the ignition of the SRBs until their burnout 123 seconds later, the only possible abort mode is a Return To Launch Site (RTLS) abort". You cannot do an RTLS abort before SRB separation, yet this says you can. Joema 23:01, 20 October 2007 (UTC)

[edit] Question About Which Site Calls Aborts

I just recently added a wikilink to NASA's Mission Control Center (located at Lyndon B. Johnson Space Center in Houston to the section about intact aborts. However, wouldn't it be correct to say that aborts occurring during the initial launch phase, when control of the mission is actually in the hands of Launch Control Center, located at Kennedy Space Center in Florida. Or are there truly no aborts that could occur before the handoff occurs (eg. once the Shuttle clears tower, or whatever precise moment is defined for when that handoff occurs, if I'm in error on timing.) - Ageekgal (talk) 12:02, 31 January 2008 (UTC)

I believe it's Johnson, since they can't do any aborts until they jettison the boosters. SchuminWeb (Talk) 14:50, 31 January 2008 (UTC)

[edit] TAL takes "less than 20 minutes"?

– the Orbiter continues along its ballistic flight path to make a landing about 45 minutes after lift-off (also in source 1 of the article)

– The time from declaration of a TAL abort to a landing is estimated at about 25-30 minutes

– Eine Landung ist dann bis zu 45 Minuten nach dem Start in Europa möglich. (Landing is possible in Europe up to 45 minutes after launch.)

say something else, and I'd consider nasa.gov and dlr.de websites more reliable than an unsourced "an astronaut". —Preceding unsigned comment added by 89.245.192.33 (talk) 11:43, 16 February 2008 (UTC)

Yes the 20 min. TAL number isn't correct. Removed this and added other abort durations from NASA sources. Joema (talk) 12:20, 16 February 2008 (UTC)

[edit] "space balls"

What about those "space balls" that were to be used in the event of an orbital problem? the astronauts would get into the inflatable balls and then transfer to another shuttle. Unfortunately though, these "balls" leaked like a sieve and the idea was scrapped. T.Neo (talk)(contribs) 12:39, 25 April 2008 (UTC)