This question isn't so much about the mini-series as it is about a technical aspect of manned space flight in general..for that I apologize.
Why did the Gemini capsules not have a launch escape tower like the Mercurys and Apollos? I know the Geminis had an ejection seat system, but my question is why......why was it designed with a different system?
Thanks.
"You said it, Curly.....ACK!"
With all the knowledgable people on this board about space travel, doesn't anyone have any insight?
"You said it, Curly.....ACK!"
The Gemini Program was originally designed to 'glide' after reentry. However the idea was scraped but the ejection seat stayed.
shareYeah, but the launch escape systems were for liftoff. Why did Gemini not have the same system to pull the capsule free from the booster in case of a problem like Mercury & Apollo?
The para-glider you speak of was an option instead of the parachutes for spashdown.
"You said it, Curly.....ACK!"
I think the answer is pretty simple. Why waste the fuel to launch an escape tower when you can use ejection seats instead? Witrh the mercury capsule it was so cramped that they probably couldn't fit in an ejection seat. The Apollo Program couldn't do it because there was only one hatch for the three crew members, where the Gemini Had two hatches, and therefore required a tower on top. Even after the tower was jettisoned in the apollo the service module could fire it's engine if an abort was needed. I'm also thinking there might have been a weight problem with the Titan II, which is only meant to carry a warhead across the ocean instead of tons of astronauts and equipment into space. I'm sure if one google's it enough they'de find an answer.
shareJust to add to the discussion - regarding the lack of an escape tower system on Gemini as opposed to Mercury/Apollo - I have never found out why. All I know is the idea was that the two astronauts would have ejected in the case of a problem with the Titan II on the launchpad or immediately after launch. Of course, in retrospect, it is interesting to speculate how physically the crew would have fared and, upto what altitude it would have been effective/safe to use!
Regarding the paraglider landing system, I have an old 1964 issue of 'National Geographic' magazine with amongst other items, an artists impression of the Gemini paraglider landing system. It looked like a large semi-inflatable triangular hanglider plus, three short ski-type skids on the capsule itself, to enable it to land back on a desert type surface. Not so ridiculous or too ambitious when one considers the Russkies were landing back on land with all their space vehicles, albeit by conventional parachutes.
It could be related to the propellants that the Titan used. If its storable propellants produced less of a fireball in the event of an explosion that the lox/kerosene used by both Mercury's Atlas and Apollo's Saturns then Gemini's ejection seats could be adequate.
shareOkay, I did some searching and think I have a reasonable explaination. Hopefully, you guys can give me more imput. The first paragragh was what I found from searching. The second paragragh is my theory. This is the best explaination I can come up with so far.
Because they had made the decision to go to the moon so early, they actually started designing Apollo BEFORE Gemini. Gemini has some newer technology available than Apollo did when they started working on it. The reason that Gemini had ejection seats instead of an escape tower like Mercury, was because the Gemini's ejection seats were thought to be an improvement. The entire cockpit was designed more like a fighter jet cockpit.
I think they couldn't put ejection seats on Apollo because of the boost protective cover. They HAD to have a boost protective cover to protect the capsule from the stresses and friction of launch because the Apollo launch must have been more stressful on the capsule then on Mercury or Gemini because the shape of the capsule wasn't as narrow and/or the launch itself was at a much higher speed.
"You said it, Curly.....ACK!"
I've just checked the Gemini history. Seems my memory was right (my previous post) about the reason for ejector seats being the less explosive propellants of the Titan 2. For Mercury and Apollo the crew had to stay in their capsule for explosion protection. For Gemini the suit provided sufficient protection, so the lighter ejection seats were a better choice.
shareYou are correct that it involved the propellants. Titan II used hypergolic (storable) propellants like those used on the Lunar Module ascent stage. If a Titan exploded, an ejector seat could outrun the fireball.
The Saturn V used liquid hydrogen / oxygen. An ejector seat would be too slow to get the astronauts away from the massive fireball in the event of an explosion, so a rocket was used.
Makes sense...thanks.
I would think the escape rocket would be less dangerous for the astronaut, though. Ejecting off a rocket on the pad wouldn't leave much time for the chute to open.
"You said it, Curly.....ACK!"
According to Jim Chamberlin (chief designer of the Mercury Mark II and Gemini's first project manager), much of it was motivated by his personal distaste for the complexity of the Mercury escape tower and associated automatic sequencing system, the large amount of time required to check out the system before flight, and associated penalties regarding reliability. See:
On The Shoulders of Titans
http://history.nasa.gov/SP-4203/ch2-5.htm
The new design attacked a number of other Mercury trouble spots. Perhaps the most troublesome was the sequencing system. Chamberlin argued that one of his chief motives for keeping systems in the new design separated was to avoid the endless complications Mercury experienced because so many sequentially controlled operations were built into it.
Why is Duct Tape like The Force?
I don't dispute any of what's been posted here but in almost every instance, the astronauts hated the Gemini ejection seats and thought they were dangerous.
Chris Kraft thought the same thing.
The clamshell doors on Gemini were relatively heavy, and the overall opening rather small. Plus the way the astronauts were seated required the ejection seats to fire up at some odd angle before going out (the astro's legs were quite a ways under the console.
The whole thing was very problematical. If the astronauts didn't break their necks, they surely would have sustained broken legs and worse on ejection being thrust up and out of the small hatch in front of them.
The aborted launch of Gemini VI speaks volumes to the above, IMHO. By the book, Wally Schira should have ejected. Every rule in the book said he should have pulled the handle. Yet he didn't. Why?
Well, the standard answer is that he didn't feel the rocket lift off-- the seat of the pants explanation. He held off, and saved the mission for another day.
I think the real reason is that he didn't trust those ejection seats or what would be left of himself and Stafford if he actually pulled the handle. He simply opted for the lesser of two evils and probably hoped like hell the rocket didn;t explode underneath him.
AE36
In Tom Stafford's autobiography, he recounted how he was hoping Schirra wouldn't have to yank the ejection handle. None of the astronauts trusted the Gemimi ejection seats. Among other factors, they'd be firing an explosive device in a 100% oxygen environment.
shareApparently John Young once saw a test-firing of an ejection seat that would've crushed an astronaut's head on something above it had they been sitting in it at the time.
He quipped that it would be "a hell of a hadeache, but a short one."
Among other factors, they'd be firing an explosive device in a 100% oxygen environment.
I believe that the Gemini were pressurized with 100% oxygen at 1 atmosphere (or slightly higher) before liftoff. They bled the pressure down to 1/5 of an atmosphere after launch. The reason for the pressure was that the spacecraft was entirely designed for the situation of positive outward pressure, not the reverse.
The Apollo spacecraft originally did things exactly the same way, which is why Apollo 1 was at 1 atmosphere during the fateful test: it was a plugs-out test of how they were going to do things for a real launch. Basically a dress rehearsal.
After Apollo 1, they changed the system, so it was pressurized with 1 atmosphere, but with a mix of a oxygen and nitrogen, and when they bled the pressure down they also added oxygen to get to 100% at the normal partial pressure. The change complicated things a bit. Among other things, they had to keep their suits and helmets sealed, because the astronauts still had to breathe 100% oxygen to avoid the bends on decompression. I guess that's not a huge complication, because they wore sealed suits and breathed 100% oxygen for awhile before getting into the spacecraft on the Mercury and Gemini missions anyway.
I forget where, but one person around at the time did offer at least a slight response to the "why were they so stupid with Apollo 1" by noting that it hadn't been a problem the 16 times before.*
_____
*Or maybe it was 14 times ... not sure what they did with the suborbital flights. I'm guessing they used 100% oxygen at 1 atmosphere against the danger of decompression, even if they didn't reduce the pressure during the flight.
Unfortunately, the Gemini and Apollo designers were unaware that the Russians had had a launch failure in which the crew had to use the abort rocket to get clear of the failing booster, and survived. It was kept secret, as were almost all failed launches. Nobody in the US programs ever had to use the abort system but in hindsight they're a very good idea. As the Challenger explosion showed, a crew module on top of a booster stack has a good chance of being blown clear of the exploding booster(s).
The escape window for the Gemini ejection seats must have been extremely small. I don't have the specs for Titan handing but even though they look slow at liftoff, big boosters get up to high mach pretty damn fast. The best ejection seats the US had at the time would probably have been those of the SR-71, which were rated for Mach-3 but only at high altitude.