By “resolved” I mean when did NASA decide that it would be reasonably safe for men to walk on the moon’s surface?
Presumably, a long time before 1969, we had figured out that the moon had no breathable atmosphere, so they’d need a self-contained breathing apparatus before men could walk on the moon. But there were other factors–the temperature of the moon, the gravity, the texture of the surface and dozens of other possible dangers that they had to verify were either not dangerous or to invent effective safeguards against. So which was the last one?
Gemini had four main goals: to test an astronaut’s ability to fly long-duration missions (up to two weeks in space); to understand how spacecraft could rendezvous and dock in orbit around the Earth and the moon; to perfect re-entry and landing methods; and to further understand the effects of longer space flights on astronauts. which was intended to test the possibility of lunar flight.
The Lunar Module and the space suits were first tested on Apollo 9, with LM descent and ascent tested on Apollo 10. So you can say “reasonably safe” somewhere between Gemini’s demonstration of long-term space flight, and the test of the space suit on Apollo 9.
Though it didn’t stop the missions (and it wasn’t a part of mission functionality), there was a concern about unknown pathogens on the Moon, and that they might return to Earth with the Apollo crews.
This concern was big enough that the Mobile Quarantine Facility, and Lunar Receiving Laboratory, were built, and was used to quarantine the crews (and their moon rocks and other samples) from Apollo 11 through Apollo 14; later crews weren’t forced to quarantine, though the moon samples were apparently kept in the LRL under strict quarantining protocols through much of the 1970s.
Before the Soviet Luna 9 and the NASA Surveyor 1 soft landings in 1966 it was unknown how deep the dust on the Moon was. If the dust was too deep, then Apollo could not land. The 5 successful Surveyor landings proved that lunar modules need not fear sinking to the bottom of an ocean of dust.
You hear that story a lot, but it’s actually the other way around: The quarantine chamber wasn’t to protect us from the astronauts; it was to protect the astronauts from us. The fear was that their immune systems might be weakened from all of the many stresses of the mission, leaving them vulnerable to opportunistic infections.
You could reasonably argue that the successful completion of Apollo 10 resolved most lingering concerns of show stopper issues. Testing use of the LM in lunar orbit, demonstrating successful separation and docking, use of the descent and ascent engines and the various abort systems. All in lunar orbit. There was no intention of trying a landing until this had all been demonstrated and sorted out.
On a mission as complex as the Apollo programme there isn’t some simple list of known dangers. It is a huge complex interacting problem with many unknown unknowns. Armstrong rated the chance of a successful mission as 50/50. He didn’t have an expectation of of a 50/50 chance of dying, but he was less than confident that he wouldn’t need to abort the mission.
As we saw, there were still a range of near show stopper issues on the landing. The famous 1201/1202 errors, but more importantly, failure of navigation to the landing site due to the inhomogeneity of the moon. The LM landed way long in a boulder strewn field with a very low fuel margin. That was fixed for the next mission - which was so pin-point in navigation they almost risked landing on top of the Surveyor lander they were aiming for.
Even after landing there was a serious moment when a frozen plug of fuel in the lines in the lander appeared to threaten an explosion and require an immediate takeoff. So for Apollo 11 they were close to pulling the pin on the landing on a few occasions. The causes all unknown unknowns at the time. There was never a final danger. Just a general confidence that they had enough margin in the systems that they could minimally get the astronauts back. In reality they were resigned to losing one in a hundred crews. History shows that this estimate was depressing accurate.
Probably the biggest question about actually walking on the surface was dust. How much and how deep? Until the Surveyor landers successfully landed there was no direct evidence that the surface was solid enough to walk on. There was a significant body of opinion that the surface was a deep layer of fine dust unable to support anything, and that any craft or astronaut would sink without trace. Arthur C. Clarke’s novel A Fall of Moondust was predicated on this idea. The dominant opinion was that this wasn’t the case, but the Surveyor craft performed enough work to characterise the surface, and to be sure. That probably marks the point where actual surface activities were assured.
Yes. Not knowing much about the project’s details, I have to assume that at one point it was “There are still too many risks to sending a man to the moon–we have to get those risks minimized much more than we have so far” which finally became “It’s a go.”
I had not heard this before, and wonder of the veracity of your statement. The only thing I can find is that it was to ensure there was no infection coming back from the moon, as well as to preserve any life in a vacuum state that might have hitched back for study.
I’ve not seen anything reliable yet that states the astronauts were to be protected from earth borne diseases because of their weakened and stressed immune systems.
Then wouldn’t the crews of earlier, longer missions that didn’t land on the moon have been expected to quarantine? For instance, Gemini VII went almost a fortnight.
As I understood, another fear was that pathogens exposed to radiation of space might mutate and become harmful. Gemini and Mercury IIRC never got above the protective Van Allen belts. (Plus the remote possibility that while going in and out of the lander they may have picked up something somehow from the moon dust.)
The post landing procedures that involved the primary recovery ship U.S.S. Hornet included precautions to avoid back-contamination by any lunar organisms, and the crew and samples were placed in quarantine.
Also PDF page 176:
The two fundamental responsibilities of the lunar sample program were to preserve the integrity of the returned lunar samples in the original or near-original state and to make practical provisions to protect the earth from possible contamination by lunar substances that might be infectious, toxic, or otherwise harmful to man, animals, or plants.
The Public Laws and Federal Regulations concerning contamination control for lunar sample- return missions are described in reference 7. An interagency agreement between the National Aeronautics and Space Administration; the Department of Agriculture; the Department of Health, Education, and Welfare; the Department of the Interior; and the National Academy of Sciences (ref. 8) confirmed the existing arrangements for the protection of the earth and defined the Interagency Committee on Back Contamination. The quarantine schemes for manned lunar missions were established by the Interagency Committee on Back Contamination (ref . 9).
The planned 21-day crew quarantine represented the period required in order to preclude the development of infectious disease conditions that could generate volatile epidemic events. In addition, early signs of latent infectious diseases with longer incubation periods would probably be detected through extensive medical and clinical pathological examinations. However, to provide additional assurance that no infectious disease of lunar origin is present in the Apollo 11 crewmembers, an extensive epidemiological program will continue for 1 year after their release from quarantine.
Well, apparently Apollo 8 was a pretty big risk; they moved the lunar orbit mission forward in the schedule by a couple of flights or so, because the Russians were testing their own giant moon rocket (N-1) and they were worried about being beaten to the moon.
In fact, it was the first crewed Saturn V mission, as well as the first mission beyond Earth orbit. So doubly risky.
I think once they were willing to take that particular set of risks, the actual landing itself was probably not considered nearly so risky.
Apollo 8 was not especially risky beyond what was initially planned. What caused it to be pulled ahead was more that the LM was way behind, and the mission to test the LM in Earth orbit - what became Apollo 9 - was simply not ready to fly. Once the Saturn 5 had reached orbit safely, that risk was done, adding on a lunar orbit really added little additional risk. Once they had had a successful launch on the rocket, the lunar orbit just built on that.
They waited for Apollo 7 to deliver a successful test of the CM in Earth orbit before committing to Apollo 8. Indeed, once Apollo 7 had delivered, the original Apollo 8 mission was rather lacklustre in content. Just riding on the Saturn 5 and repeating Apollo 7. So the lunar mission made a lot of sense.
The technical risk would have been a failure of the CM engine to get them home. But that had already been well tested by Apollo 7. There was little doubt that the systems were good. All they did was travel further.
This underlined the “all up test” regime that was a big contributor to the speed of the programme.
Surely this wasn’t a serious concern, outside of science fiction stories.
A little thought on gravity and gravitational compression would show that the dust would been compressed into rock by then. After all, that’s just how all the planets were created in the first place!
Even on the Moon, the surface dust isn’t compressed into rock. It forms a loose, dry layer known as regolith. But this regolith is made up of a wide range of irregular particles, which are closely fitted together and have a certain amount of cohesion, so it is like digging into dusty gravel. When the astronauts tried to poke various implements into it, the regolith resisted their efforts quite efficiently.
It was very much a concern (although my comment about sinking to the bottom of an ocean of dust is a bit of an exaggeration.) Armstrong’s first words after “…one giant leap for mankind.” were “And the surface is fine and powdery. I can pick it up loosely with my toe. " Even after the Surveyor missions, NASA was still uncertain about the stability of the lunar soil and how it might impede manned landings.
