Why didn't Gemini have an escape tower?

[Capt. Hunt]

Sorry, but I have to do this:

Space shuttle had ejection seats. THEN NOTHING.

And btw, gemini had the retro rockets to escape with, underneath the capsule.

I'm pretty sure that after STS-4 they decided that the Ejection seats wouldn't have helped if something happened to the Shuttle, and I'm also pretty sure that if they thought they were any good they would have put them back in after STS-51-L. Besides, before STS-5 it only had a crew of two, two seats weigh a lot less then the seven seats it would have normally carried

Edited January 13, 2014 by Capt. Hunt

[rpayne88]

They didn't have ejection seats (on the shuttle,) but they did have parachutes. I'm guessing the idea was ditch the tank, blow it up, and establish a glide back to the runway. If they weren't going to make it, then trim the shuttle to maintain its best glide speed and bail out.

[Drunken Hobo]

How would ejection seats have worked in a shuttle? You'd need to tear a hole in the roof to allow the astronauts to escape, but you'd need some pretty serious exposives to tear through the Shuttle's roof, not to mention all of the instrument panels and things that get in the way.

Or am I just listing the reasons it wouldn't have worked?

[Whirligig Girl]

How would ejection seats have worked in a shuttle? You'd need to tear a hole in the roof to allow the astronauts to escape, but you'd need some pretty serious exposives to tear through the Shuttle's roof, not to mention all of the instrument panels and things that get in the way.

Or am I just listing the reasons it wouldn't have worked?

you open a door in the top I guess.

[Capt. Hunt]

They didn't have ejection seats (on the shuttle,) but they did have parachutes. I'm guessing the idea was ditch the tank, blow it up, and establish a glide back to the runway. If they weren't going to make it, then trim the shuttle to maintain its best glide speed and bail out.

nope, the first 4 missions were equipped with Ejection seats:

This wikipedia article on space shuttle abort modes talks about them, and also mentions why they were removed:

http://en.wikipedia.org/wiki/Space_Shuttle_abort_modes#Ejection_escape_systems

it doesn't mention how the seats would have punched out, though, I assume there was some sort of jettisonable hatch that was later permanently sealed.

Edited January 14, 2014 by Capt. Hunt

[Ignamious]

If i remember correctly, the Pilots wanted more controls too, originally it was mostly if not all "computer" controlled. i might be thinking of a different mission profile, lots of useless information knocking about in this head in a semi-jumbled mass.

[DerekL1963]

How would ejection seats have worked in a shuttle? You'd need to tear a hole in the roof to allow the astronauts to escape, but you'd need some pretty serious exposives to tear through the Shuttle's roof, not to mention all of the instrument panels and things that get in the way.

Using FLSC (Flexible Linear Chaped Charges), you could remove the shell of the crew compartment and fuselage skin with less than a pound of explosives per seat. (It's not like the skin is all that thick.)

[Nibb31]

Columbia had 2 ejection seats for the first flight. They would have blown two hatches above the seats to eject. The hatches and extra structural reinforcements were the reason she was the heaviest of the fleet. She also had more instrumentation, sensors and flight recorders that were installed for those experimental flights and were never removed. They actually proved crucial in the investigation of the accident.

Remember that in 1984 on her first flight, the whole concept of the Space Shuttle was totally untested. They had done no unmanned test flights on the vehicle like on previous vehicles, and computer simulations were rudimentary in those days. This was the most complex machine ever built by humans, yet it had to work flawlessly the first time.

Crippen and Young had balls of steel to fly that thing!

[Agent86]

They didn't have ejection seats (on the shuttle,) but they did have parachutes. I'm guessing the idea was ditch the tank, blow it up, and establish a glide back to the runway. If they weren't going to make it, then trim the shuttle to maintain its best glide speed and bail out.

I recall an episode of stargate where Sam carter in an alternate reality was a shuttle pilot who ordered her crew to evac via parachute while she steered the ship away from a city and out into the ocean where she died on it. No real reason to bring it up, stargate just rocks is all.

[Nibb31]

The Shuttle didn't have a LES, but it had several abort modes that involved dumping the ET and gliding back to the landing site after doing a roll maneuver. It was risky, and therefore never tested outside of a simulator. This video shows what it would have looked like to do a RTLS with multiple engine failures (in this case, they lose too many engines, so they have to ditch the shuttle and bail):

www.youtube.com/watch?v=t6fSUaZlsWw

Between STS-5 and STS-51-L there was no way for the crew to bail out, so if the Shuttle wasn't high enough to glide to a landing site, they would have ditched into the ocean, which was not survivable. It wasn't possible to bail because the crew hatch was located just in front of the wing edge. After the Challenger accident, they devised a method with a special extendable pole so that the crew could slide away and clear the wings. The ACES suits were also redesigned in orange and parachutes were added.

More info here:

http://en.wikipedia.org/wiki/Space_Shuttle_abort_modes

[Seret]

All the shuttle escape systems were a bit of a bodge, and there were big chunks of launch where there was nothing. One of the big problems with the shuttle was that the whole design was just a mess of compromises. Lots of lessons to be learned there for any future attempts at a similar spacecraft.

As for ejection seats, you normally have something over your head when you pull the handle. Aircraft canopies aren't lightweight pieces of the structure, and there are aircraft such as bombers that have ejection seats inside the fuselage. Various approaches have been used. You can eject the whole cockpit (a la B-1 and F-111) which is good for high altitude and speed, but heavy. Or you can either cut the canopy/structure with a cutting charge, or use mechanical or pyrotechnic means to jettison them. Heck, we've even managed to shoehorn ejection seats into helicopters.

[Nikolai]

I recall an episode of stargate where Sam carter in an alternate reality was a shuttle pilot who ordered her crew to evac via parachute while she steered the ship away from a city and out into the ocean where she died on it.

In Stephen Baxter's Titan, the Columbia is destroyed in a crash landing. The pilot has enough time to get the other astronauts out via parachute and tries to bring the orbiter down safely, but the hydraulics operating the control surfaces fail at the last moment.

[Capt. Hunt]

the obvious problem with ejection seats on the shuttle once it was in service was that the bulk of the crew is on the mid deck during launch, a downward ejection ala B-52 would have been impossible because of the ET, let alone the heatshield and all the other stuff in the belly of the shuttle. Not to mention that the only time during the launch where ejection would be a viable abort at all would have been while the SRBs were still firing, meaning that anyone who punched out would have been fried in the rocket exhaust.

[Seret]

Not to mention that the only time during the launch where ejection would be a viable abort at all would have been while the SRBs were still firing, meaning that anyone who punched out would have been fried in the rocket exhaust.

Even then they'd only be useful for the very early part of the flight, I'd imagine you'd be well outside the ejection envelope pretty quickly.

I suspect they were more interested in having them on board for the free flight landing tests than for actual space missions. Being the world's heaviest most brick-like glider meant there was no option to go around, and that if things went wonky during a landing the test pilots would have enjoyed having the option to bang out. That kind of thing is good for morale.

[DerekL1963]

All the shuttle escape systems were a bit of a bodge, and there were big chunks of launch where there was nothing. One of the big problems with the shuttle was that the whole design was just a mess of compromises. Lots of lessons to be learned there for any future attempts at a similar spacecraft.

Any real world piece of hardware, from your coffee cup to the Space Shuttle, is a mess of compromises. It's only in imaginary worlds and cloud cuckoo land that there are no compromises.

But as a former submariner, these discussions of Shuttle escape and abort systems and the probability (or lack thereof) of their success alternately makes want to laugh and cry. Thousands of my brothers (and now a welcome handful of sisters) are at se and at risk even as I type... and nobody cares that our systems only cover a fraction of our operating envelope or require an unlikely chain of events to succeed. And we've done this daily, in peace and in war, for decades. But we're not pseudo celebrities or any other kind of famous. We're nameless and faceless other than to our friends or family.

Your focus on the life of the astronauts is misplaced anyhow. Astronauts are cheap and expendable - for every one who ever rode a Shuttle, there's a dozen or more equally qualified candidates who'll never even be an astronaut. It's the Shuttle that's the problem - it's an expensive and difficult-to-impossible to replace national asset. The hardware is the scarce part, and while not nearly as damaging from a public relations point of view, the loss of the hardware has the most actual impact on the program.

[Seret]

Any real world piece of hardware, from your coffee cup to the Space Shuttle, is a mess of compromises.

Some much more so than others.

I think people are well aware that submariners are riding around in a deathtrap. We just all think you're a bit strange for wanting to do it in the first place.

[rdfox]

For the record, I've always heard that the big reason that Gemini used ejection seats was the planned paraglider landing, which, being on land, offered little leeway for problems, and it was felt that it would be a good idea for the crew to have an escape capability during the landing. The seats, along with the individual hatches (which were needed more because there was no way to use a single hatch to stuff two men in pressure suits into a space as small as the Gemini capsule--remember, it was originally called "Mercury Mark Two"--and were clamshell because they wanted to have EVA capability) then ate up enough of the Titan II's payload capacity that it meant that a proper LES tower wouldn't be possible (because it would make the spacecraft too heavy).

The pressure suits and ejection seats used on Gemini (and on STS-1 through STS-4!) were the exact same models used on the SR-71, with an envelope that went from zero-zero to about Mach 3.5 and/or 120,000 feet. (Columbia's ejection seats, BTW, remained, albeit deactivated, until after STS-51L, simply to save time during a period when Shuttle launches were insanely frequent. The hatches, though permanently sealed, remained to the end, but the seats were removed and replaced with the same ones as the others had during the post-51L standdown, to reduce vehicle weight.)

And Gemini's planned Rogallo inflatable wing (parafoil) recovery system did have one lasting legacy on the spacecraft--it's why the Gemini recovery procedures always included a transition from a one-point (nose only) to a two-point (nose and tail) suspension system. Since the spacecraft was designed to provide cushioning of impact forces in a horizontal landing attitude, even using a circular parachute, it had to come down in that same attitude to protect the crew on the 20mph splashdown--thus they retained the aft parachute mount point and blowing the clip to swing it into two-point suspension mode once the parachute had deployed.

As for submariners, we don't think you're strange for riding around in a deathtrap (that describes a LOT of jobs in all branches of the military, starting with helicopter pilots); we think you're strange for volunteering to serve on a ship that's actually designed to sink!

(Hey, I'm going into naval architecture, I'm allowed to make that kind of joke...)