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After the Challenger disaster, the Space Shuttle astronauts were outfitted with pilot spacesuits equipped with parachutes and internal emergency oxygen supplies, and the space shuttle was equipped with a jettison-able hatch and an extendable pole so that astronauts could bail out of a space shuttle that was not going to be able to land safely. This system was somewhat infamous because it would (probably) not have saved the astronauts from either of the two fatal Space Shuttle accidents and its use was generally contingent on the Space Shuttle being intact, controllable, and generally not suffering the kind of catastrophic emergency that necessitates bailing out.

What I am curious about is just how strong the requirements for a low-altitude stable glide for bailout actually was. Could crew, for example, plausibly throw themselves out of the crew compartment of a disintegrating shuttle as long as it wasn't rapidly tumbling or subject to too high of a G-load to clamber around?

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The escape pole / hatch jettison system was only certified to work in a controlled gliding flight situation. See Mode VIII Egress in the Crew Escape Workbook

That doesn't mean that the crew couldn't try to save themselves though. There was a Loss of Control / Break-up procedure in the Ascent Checklist.

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My feasibility estimate: slim.

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  • $\begingroup$ Is the biggest difficulty here just the physical clambering out of the vehicle and then not colliding with debris? $\endgroup$ – ikrase Mar 25 at 9:40
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    $\begingroup$ I think so. If the Orbiter was in a random 3 axis tumble, for the flight deck crew to get out of their seats and through the flight deck / middeck access hole and out the hatch in their clumsy suits would be extremely difficult. If the vehicle just somehow vanished, the entry heating would be a problem too for a lot of the entry trajectory. $\endgroup$ – Organic Marble Mar 25 at 12:13
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    $\begingroup$ The Columbia crew survival report talks about some of these difficulties. Discussion here and link to the report: spaceflightnow.com/shuttle/sts107/081230report $\endgroup$ – Organic Marble Mar 25 at 12:20
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    $\begingroup$ Some background info: I was personally involved in the management of the associated testing that was done back in the mid-90's at Edwards Air Force Base. We had a small cadre of "test-jumpers" assigned. IIRC, the test bed was a modified C-141 aircraft. The primary hazard facing the test jumpers was contact with the wing leading edge. We considered this testing to be pretty dangerous and it was expensive. One can surmise that only a limited set of conditions were tested. For the record, I remember thinking that those guys were truly crazy... $\endgroup$ – Digger Apr 25 at 16:06
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There's certainly a cost-weight-feasiblity effect. If you compare the Shuttle seats with the ejection seats used for high-speed, relatively high-altitude, military jet aircraft, the jets' seats have a massive ejection mechanism -- not to mention that they're designed to crash thru the canopy (in case of canopy eject failure). The cost of either designing the Shuttle seats and Shuttle body to do a similar action would be horrendous.

Ejecting at supersonic speeds is usually fatal. Brian Udell is a rare survivor. Ejecting at extreme altitudes is an additional problem. You can't deploy a chute until the atmosphere is reasonably thick and you (or your capsule) have been slowed sufficiently from air-drag tht the chute won't rip to shreds upon opening. So now we're almost proposing a 9-person Apollo capsule analog to save a Shuttle crew.

If you plan instead to wait until the Shuttle has gone subsonic and is more or less gliding stable, then most of the "it just broke up and destroyed everything" scenarios have already happened.

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    $\begingroup$ Columbia as first delivered had ejection seats installed but only for the front-seaters. $\endgroup$ – Organic Marble Mar 25 at 15:55
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    $\begingroup$ This question is about the space shuttle as built or with small modifications, not about hypothetical variants with complex escape systems. $\endgroup$ – ikrase Mar 26 at 1:53
  • $\begingroup$ @ikrase my point was to show why these hypothetical options were not implemented. $\endgroup$ – Carl Witthoft Mar 26 at 13:05

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