Re: Why wasn't escape tower used on Gemini?



Dale wrote:


Ejection seats weren't an option with Apollo. Were the lessons learned
with the Mercury escape system readily applied to Apollo, or were the two
on separate but parallel design paths, and a lot of stuff had to be learned
all over again with the Apollo LES?



The Apollo system was a to some extent a combination of the Mercury fully-automatic escape system, and the Gemini completely manual one. If something went seriously wrong with the Saturn the system would automatically activate the escape tower; less serious problem were brought to the crew's attention and they then decide whether to fire the escape tower on their own.
It was a nice set-up if you had the time and money to do it that way, and on Apollo they did.
It certainly paid off, as otherwise the lightning strike on Apollo 12 that knocked the computer off-line would have been one thing that would have triggered a fully automatic system. The way it was the mission was saved by having it fall into the hands of the astronauts to deal with.
It's hard to picture what an Apollo with ejection seats would look like; I imagine the main hatch would blow off for the center crewman, and shaped charges would cut two openings in the outer hull for the other two crew members to eject through.
One problem with this approach would be the weight of the ejection seats - Apollo used crushable honeycomb shock absorbers on the seat support structure to take up some of the force of impact of landing after reentry, and the weight of the astronauts plus ejection seats would have meant that the shock absorbers would have to be greatly beefed up.
Also, trying to eject out of the fireball of a disintegrating Saturn V would have taken a mighty impressive performance seat.
Although the ejection seats are always associated with Gemini, the spacecraft had two escape systems; once altitudes and speeds were reached that made the seats unusable, the spacecraft could be separated from the vehicle by firing all four of its retrorockets simultaneously...though not usable on the pad like an escape tower, this would at least get the spacecraft detached from the booster.

Pat
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