More like a Robert A. Heinlein screenplay Project Moonbase - Wikipedia
Worth seeing the fortunately-never-needed speech that William Safire wrote for President Nixon: IN EVENT OF MOON DISASTER – Letters of Note
To my knowledge Safire’s memo was never vetted by NASA or any other aerospace professional – it was a politician’s idea. In reality the “stranded on the moon alive” described in the memo was very unlikely. Apollo was dangerous and they could died various ways – stranded in orbit, crash into the moon, Saturn launch vehicle disintegrate on takeoff, etc. But being stranded alive on the moon yet healthy enough to talk to earth was unlikely – yet that one scenario is what captured the politician’s imagination.
The entire Apollo 11 approach trajectory and landing site choice was very conservative. Both flight rules and common sense called for extremely low forward/lateral velocity at touchdown. Even if totally blinded by dust, the landing radar showed horizontal velocity. No pilot in their right mind would allow high horizontal or vertical velocity at the touchdown point.
While LM touchdown and liftoff constraints in terms of velocity and tilt were sometimes described as limited, in fact the LM fairly high limits. In this thread we discussed the max permissible tilt angle for a successful lunar liftoff; it was very high – it could be tilted 45 degrees and still take off: LM max tilt angle for safe lunar liftoff? The LM could take off and reach orbit with no computer whatsoever, just using manual steering and a stopwatch.
So a crash gentle enough to preserve the astronauts but hard enough to preclude a takeoff was very unlikely. Re a Martin Caidin-style Marooned on the Moon scenario, where “it just won’t start”, that also was extremely unlikely. There were no fuel cells, no turbopumps, no ignitors, no engine gimbal in the ascent stage, no regenerative cooling in the engine – it was as simple as could be made, with multiple abort opportunities during powered descent and just after touchdown had anything looked wrong.
The Safire memo also envisions NASA cutting off communication with the astronauts at some point. Again, this is a politician’s view. NASA was in constant telemetric communications both spacecraft the astronauts while on lunar surface. In the event of a looming possibly-fatal disaster, this would be maintained up to the very end (and beyond) for diagnostic and technical forensic reasons.
The Apollo astronauts themselves were asked what they would do if stuck on the moon. They said they’d be 100% focused on solving the problem, no matter how slim the chance – until their last breath of air. They wouldn’t be sitting around talking about their life decisions or wasting precious minutes saying goodbye to anyone. With Apollo, contingency procedures were usually possible – provided nobody wasted time or foolishly cut off communications thinking it was too late.
A side question: In researching emergency lunar scenarios I came across the computationally simplest possible lunar surface to orbit trajectory: Fire the rockets to go straight up with a peak height of the intended orbit, then transversely to achieve the orbital velocity. How much less efficient is this than following a curved trajectory? The simplicity is wonderful but I presume fuel would be at an absolute premium.
That would entail a major efficiency hit due to gravity drag, aka gravity losses. Any time a launch vehicle (even on the airless moon) ascends vertically it is losing performance since gravity subtracts from the vertical thrust vector. Gravity loss - Wikipedia
This is why all launch vehicles tilt over ASAP. When launching from earth they must retain a vertical rise longer to get out of the thick atmosphere. On the moon the LM tilted over very quickly to avoid gravity drag. After just a few seconds of vertical rise it pitched over 50 degrees from vertical, and this steadily increased to 90 degrees.
The shuttle’s gravity losses were about 16% of orbital velocity – IOW it had to carry fuel to provide an extra 1,200 meters/sec delta V above and beyond orbital velocity, simply because the vertical ascent phase bled away that much performance. Other launchers are similar. This is despite them pitching over ASAP.
If that is any guide it would imply that a lunar launcher which went straight up and did a late pitch over might have over 20-30% performance loss vs an optimize ascent trajectory using the early pitch over made possible by the airless environment. But this is just a guess.
In this Apollo 17 lunar liftoff video you can see how rapidly the LM pitches over: https://www.youtube.com/watch?v=9HQfauGJaTs
joema, the Shuttle isn’t the best guide because first it has to overcome atmospheric drag, and second it has to accelerate slowly enough to not subject the crew to punishing G- forces. The Moon has no atmosphere, the maximum acceptable acceleration would be a higher multiple of the Moon’s gravity and the minimum circular orbit would be lower.
For a (slightly idealized) lunar escape scenario the efficiency loss would be to compare an elliptical orbit with periapsis at the lunar surface and apopsis at orbit plus a circlizing burn, with the circular orbit velocity plus the pop-up burn; the pop-up burn would equal the velocity at the lunar surface of an elliptical orbit with apopsis at orbital height and periapsis at the Moon’s center. I don’t know if that would be a fixed percentage of efficiency loss or if it would be variable depending on the height of the final orbit; I don’t have the math skills to calculate it.
As I said, other launch vehicles are similar to the Shuttle. The Saturn V and Titan IV actually have greater gravity losses, despite not using throttleable engines to minimize max g load.
The question was what would the proportional losses be (relative to the standard ascent trajectory) on the moon. Since the LM flew an ascent trajectory that was only possible in that vacuum environment, the relative percentage loss of a pop-up trajectory would seem significant. The 1/6 g lunar gravity would seem to reduce the gravity drag vs earth, but then lunar orbital velocity is only about 6,000 ft/sec (1828 m/s), vs 25,600 ft/sec (7823 m/s) on earth. The question is not the absolute gravity losses, but what are the relative losses vs lunar orbital velocity when comparing traditional vs pop-up ascent trajectories.
Exactly what is hard to say since there is not a simple formula for gravity losses. It must be devised by simulation. However in general a vehicle which ascends slowly vertically before pitching over (like the Saturn V) will have greater gravity losses than one which ascends quickly off the pad (like the shuttle).
The LM ascent stage had a liftoff thrust-to-weight ratio of 2.1-to-1, increasing to 4.4-to-1 (or 4.4 g) at cutoff. So it accelerated quite smartly. That would seem to reduce gravity losses even in a more vertical trajectory, but the comparison is to the immediate pitchover standard ascent which has very low losses.
It’s a little-known fact [*not actually a fact] that Safire wrote a whole series of speeches; one of which-- returning to the OP-- was for the event of astronauts disobeying orders. See the third one here
No doubt it could have been adapted for a Apollo 10 landing.
“In event spacecraft hits U.S.S. Hornet, crushing Nixon.”
:dubious:
“Fate has ordained that the men who went to the moon in peace have been devoured by gigantic extraterrestrial slugs…”
One would certainly hope that giant, people eating slugs are extraterrestrial. :dubious: