5 ms·

Really? Did not know this. Any info as to why they stopped doing that?

rangibaby 7y ago
Weight
catalogia 7y ago
Only the pilot and copilot had ejection seats, the rest of the crew couldn't also have ejection seats (I'm not sure if it was specifically weight, volume, or orientation/configuration that was the limiting factor. I think maybe a combination of all three.) STS-1 through STS-4 (all using Columbia) only had a pilot and copilot, no other crew. For STS-5 and STS-9 when there was more crew, they flew with the ejection seats disabled. After STS-9 the seats were removed. I don't have a source saying it specifically, but I think they weren't keen on operating a shuttle where two of seven crew could survive but the other five had no chance. It must have also saved weight and space too.
na85 7y ago
They were kinda useless, operationally-speaking. Half the crew members were on the lower deck and surrounded by significant hull structure, and so couldn't eject. The first two shuttles were only designed around a crew of 2 where this design made more sense. Irrespective of that, the ejection seats only work for a very limited period of the shuttle's operating envelope. IIRC it's something like only the first 2 minutes of flight where the ejection seats could be used. And in most cases where you'd be able to eject, the solid rocket boosters were still firing and it was theorized that as the shuttle passed a pilot who had just ejected, the exhaust gases would ruin the parachute and/or kill an ejecting pilot anyways. By the time the SRBs burnt out, the shuttle was too high/fast to eject.
- catalogia 7y ago
  > The first two shuttles were only designed around a crew of 2 where this design made more sense. Only the first I think, unless you're count Enterprise (which couldn't go to space.) Challenger (the second orbit-capable shuttle) never flew with less than four crew. Incidentally, the ejection seats of questionable worth in Columbia weren't without NASA precedent; the Gemini program also used ejection seats which similarly had a pretty narrow window of usefulness at best. One of my favorite pictures ever is this shot of the Gemini capsule with both hatches open, giving a pretty clear view of how the seats would have worked: https://upload.wikimedia.org/wikipedia/commons/e/e2/Armstrong_and_Scott_with_Hatches_Open_-_GPN-2000-001413.jpg https://upload.wikimedia.org/wikipedia/commons/e/e2/Armstron...
  - greedo 7y ago
    That's a great photo! Really illustrates how small the capsule was.
  - deleted 7y ago
    [deleted]
  - beerandt 7y ago
    Since Enterprise was initially intended to go to space, (to be completed after the flight tests) I'd count it for design purposes. STS-1 through STS-4 all had a crew of 2 on Columbia.
00N8 7y ago
I read that at least one shuttle commander thought the ejector seats would've been useless anyway b/c if you used them while the solid rocket boosters were still running you'd get burned up & lose your parachutes from the SRB exhaust - and your altitude & velocity would be too high to eject by the time you'd be safe from the SRBs
- catalogia 7y ago
  They were zero-zero seats (capable of ejecting at zero airspeed/altitude, aka on the ground), so they conceivably would have been useful during some of the return trip, including sitting on the runway after landing. Understandably that was probably not the part of the flight the astronauts were most worried about though.
beerandt 7y ago
Think of the situation that puts the commander and pilot in- they're the ones flying the shuttle; no one else can eject. If they eject, they are essentially abandoning the rest of the crew to die. It's the antithesis of the captain going down with his ship. Initial unpowered glide tests were the only flights where ejection was even likely survivable, and this was the reason the seats were ever installed in the first place. (Only on the first two orbiters.) Any other use was an extreme long shot. Of course all the abort modes ended up being fairly convoluted and unsurvivable to some extent, except abort to orbit. The "contingency" aborts were especially absurd, which depended on burning off most of the remaining fuel (which would take longer, given it would likely be used in the event of an engine failure), then orienting the shuttle into a position where the crew could attempt a midair bail out. Think about that. RTLS was a close second, for single SSME loss in the first 4 minutes. It was a 25 minute (!) abort process that involved building up enough speed and altitude so that the shuttle could be flipped around and "put in reverse" to return to the launch site. This involved a certain amount of time at near zero horizontal velocity, so the altitude was needed to permit some time of "free fall" while reversing direction. It also put the orbiter well outside of it's survivable stress envelope, and subjected the crew to extreme g-forces. It was highly questionable that even a perfectly functioning shuttle could have executed the abort, let alone a malfunctioning one. >Astronaut Mike Mullane referred to the RTLS abort as an "unnatural act of physics" >John Young:"RTLS requires continuous miracles interspersed with acts of God to be successful" These were abort modes that were considered survivable. There were another set of scenarios that were considered not survivable: LOCV for Loss of Crew and Vehicle. It was this level of absurdity that led to the NASA culture of basically ignoring some cherry-picked risks, ultimately leading to Challenger and Columbia. https://spaceflight.nasa.gov/shuttle/reference/shutref/sts/aborts/rtls.html https://spaceflight.nasa.gov/shuttle/reference/shutref/sts/a... http://www.nasa.gov/centers/johnson/pdf/383441main_contingency_aborts_21007_31007.pdf http://www.nasa.gov/centers/johnson/pdf/383441main_contingen... https://en.m.wikipedia.org/wiki/Space_Shuttle_abort_modes https://en.m.wikipedia.org/wiki/Space_Shuttle_abort_modes
- jabl 7y ago
  > Think of the situation that puts the commander and pilot in- they're the ones flying the shuttle; no one else can eject. > If they eject, they are essentially abandoning the rest of the crew to die. It's the antithesis of the captain going down with his ship. The Avro Vulcan bomber used by the RAF during the cold war had ejection seats for the pilot and co-pilot, and the 3 other crewmen had just parachutes. There were several accidents where the pilots managed to eject successfully but all the other crewmen were killed.

Weight

Only the pilot and copilot had ejection seats, the rest of the crew couldn't also have ejection seats (I'm not sure if it was specifically weight, volume, or orientation/configuration that was the limiting factor. I think maybe a combination of all three.) STS-1 through STS-4 (all using Columbia) only had a pilot and copilot, no other crew. For STS-5 and STS-9 when there was more crew, they flew with the ejection seats disabled. After STS-9 the seats were removed. I don't have a source saying it specifically, but I think they weren't keen on operating a shuttle where two of seven crew could survive but the other five had no chance. It must have also saved weight and space too.

na85 7y ago

They were kinda useless, operationally-speaking. Half the crew members were on the lower deck and surrounded by significant hull structure, and so couldn't eject. The first two shuttles were only designed around a crew of 2 where this design made more sense. Irrespective of that, the ejection seats only work for a very limited period of the shuttle's operating envelope. IIRC it's something like only the first 2 minutes of flight where the ejection seats could be used. And in most cases where you'd be able to eject, the solid rocket boosters were still firing and it was theorized that as the shuttle passed a pilot who had just ejected, the exhaust gases would ruin the parachute and/or kill an ejecting pilot anyways. By the time the SRBs burnt out, the shuttle was too high/fast to eject.

catalogia 7y ago
> The first two shuttles were only designed around a crew of 2 where this design made more sense. Only the first I think, unless you're count Enterprise (which couldn't go to space.) Challenger (the second orbit-capable shuttle) never flew with less than four crew. Incidentally, the ejection seats of questionable worth in Columbia weren't without NASA precedent; the Gemini program also used ejection seats which similarly had a pretty narrow window of usefulness at best. One of my favorite pictures ever is this shot of the Gemini capsule with both hatches open, giving a pretty clear view of how the seats would have worked: https://upload.wikimedia.org/wikipedia/commons/e/e2/Armstrong_and_Scott_with_Hatches_Open_-_GPN-2000-001413.jpg https://upload.wikimedia.org/wikipedia/commons/e/e2/Armstron...
- greedo 7y ago
  That's a great photo! Really illustrates how small the capsule was.
- deleted 7y ago
  [deleted]
- beerandt 7y ago
  Since Enterprise was initially intended to go to space, (to be completed after the flight tests) I'd count it for design purposes. STS-1 through STS-4 all had a crew of 2 on Columbia.

00N8 7y ago

I read that at least one shuttle commander thought the ejector seats would've been useless anyway b/c if you used them while the solid rocket boosters were still running you'd get burned up & lose your parachutes from the SRB exhaust - and your altitude & velocity would be too high to eject by the time you'd be safe from the SRBs

catalogia 7y ago
They were zero-zero seats (capable of ejecting at zero airspeed/altitude, aka on the ground), so they conceivably would have been useful during some of the return trip, including sitting on the runway after landing. Understandably that was probably not the part of the flight the astronauts were most worried about though.

beerandt 7y ago

Think of the situation that puts the commander and pilot in- they're the ones flying the shuttle; no one else can eject. If they eject, they are essentially abandoning the rest of the crew to die. It's the antithesis of the captain going down with his ship. Initial unpowered glide tests were the only flights where ejection was even likely survivable, and this was the reason the seats were ever installed in the first place. (Only on the first two orbiters.) Any other use was an extreme long shot. Of course all the abort modes ended up being fairly convoluted and unsurvivable to some extent, except abort to orbit. The "contingency" aborts were especially absurd, which depended on burning off most of the remaining fuel (which would take longer, given it would likely be used in the event of an engine failure), then orienting the shuttle into a position where the crew could attempt a midair bail out. Think about that. RTLS was a close second, for single SSME loss in the first 4 minutes. It was a 25 minute (!) abort process that involved building up enough speed and altitude so that the shuttle could be flipped around and "put in reverse" to return to the launch site. This involved a certain amount of time at near zero horizontal velocity, so the altitude was needed to permit some time of "free fall" while reversing direction. It also put the orbiter well outside of it's survivable stress envelope, and subjected the crew to extreme g-forces. It was highly questionable that even a perfectly functioning shuttle could have executed the abort, let alone a malfunctioning one. >Astronaut Mike Mullane referred to the RTLS abort as an "unnatural act of physics" >John Young:"RTLS requires continuous miracles interspersed with acts of God to be successful" These were abort modes that were considered survivable. There were another set of scenarios that were considered not survivable: LOCV for Loss of Crew and Vehicle. It was this level of absurdity that led to the NASA culture of basically ignoring some cherry-picked risks, ultimately leading to Challenger and Columbia. https://spaceflight.nasa.gov/shuttle/reference/shutref/sts/aborts/rtls.html https://spaceflight.nasa.gov/shuttle/reference/shutref/sts/a... http://www.nasa.gov/centers/johnson/pdf/383441main_contingency_aborts_21007_31007.pdf http://www.nasa.gov/centers/johnson/pdf/383441main_contingen... https://en.m.wikipedia.org/wiki/Space_Shuttle_abort_modes https://en.m.wikipedia.org/wiki/Space_Shuttle_abort_modes

jabl 7y ago
> Think of the situation that puts the commander and pilot in- they're the ones flying the shuttle; no one else can eject. > If they eject, they are essentially abandoning the rest of the crew to die. It's the antithesis of the captain going down with his ship. The Avro Vulcan bomber used by the RAF during the cold war had ejection seats for the pilot and co-pilot, and the 3 other crewmen had just parachutes. There were several accidents where the pilots managed to eject successfully but all the other crewmen were killed.