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Old 07-22-2016, 06:14 AM
joema is offline
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Quote:
Originally Posted by bob++ View Post
I am more interested in what Neil and Buzz might have done after finding that the LM was broken but they could still communicate with Earth. These guys were highly motivated, brave and resourceful, so I can't see them just sitting down and giving up. They would know that rescue was not possible, but I think that they would want to make whatever contribution they could before the end. I wonder if there was a preconceived protocol for that situation?
The draft speech "In Event of Moon Disaster" was in 1969 by Nixon aid William Safire, possibly at the direction of Chief of Staff H.R. Haldeman: http://www.history.com/news/what-if-...ing-had-failed

It might have been influenced by the Martin Caiden book "Marooned", originally written in 1964 but revised in 1968 to fit Apollo. In that novel Apollo astronauts were stranded in earth orbit while their oxygen slowly ran out. It was also a 1969 movie, released in November -- after the July moon mission.

The speech was a political aide's speculative view of a scenario. It was not vetted by NASA engineers or checked for technical feasibility. It clearly implies a "stranded alive on the lunar surface" situation.

In fact there was probably relatively little chance of this specific case happening. It was a risky mission and they could have died en route, as nearly happened in Apollo 13. They could have crashed into the moon, as nearly happened on Apollo 10. If they tried to land without landing radar (which temporarily failed on Apollo 14) they could have crashed into the moon and died or exceeded the descent rate for a successful staged abort, then crashed in the ascent stage and died. They could have been marooned in lunar orbit if the SPS engine had a complete gimbal motor failure (one gimbal motor became unstable on Apollo 16). They could have died on the moon due to a space suit failure. They could have died during lunar liftoff if all the pyros didn't sever the ascent stage. However the chance of being alive on the moon, able to communicate yet unable to take off was probably quite low -- if nothing else because the other failure modes were proportionately higher.

The Lunar Module ascent stage was designed with extreme simplicity, even at a significant performance cost. The propulsion system had no pumps or igniters. There were no fuel cells like failed on Apollo 13 -- only batteries. Unlike the Service Module it used only pressurized gaseous oxygen, not cryogenic oxygen (which blew up on Apollo 13). The propulsion plumbing used double redundant valves. It had double redundant computers and could probably reach orbit without any computer whatsoever -- that was a practiced contingency. The reaction control thrusters had a separate non-computerized analog electrical path, and separate contingency activation solenoids. The engine had no complex regenerative cooling, thereby greatly simplifying plumbing. The engine was not gimbaled like on the Service Module, just bolted in a fixed position.

Nominally the LM was supposed to land with a maximum tilt angle of +/- 12 degrees from local vertical. However under extreme conditions it could probably have lifted off if one leg became caught on a crater rim during landing and the entire vehicle was tilted sideways 70 degrees. This was studied in the 1966 paper "Apollo Lunar Module Landing Strategy" by Donald C. Cheatham.

Something could easily have gone fatally wrong during powered lunar descent or ascent. However it is unlikely those failure modes would have produced a "stranded alive on the lunar surface and able to communicate with earth" scenario -- which is the *sole* scenario discussed in the William Safire speech. Rather those would have produced an immediate fatality, or a lingering helpless situation in space -- neither of which were addressed by the Safire speech.

Some of the Apollo astronauts have been asked about this exact situation and they replied as you'd expect -- they would keep working on the problem up to the last second of life. This would be with earth's help, via telemetry and voice -- unless someone stupidly cut off communications before then as suggested in the Safire speech.