One of the last dangers to be recognised before the missions were launched was the radiation in the Van Allen Belt. These were discovered in 1958.
The transfer orbits between the Earth and the Moon had to be diverted significantly to avoid the worst of this radiation.
Look up Thomas Gold.
Andrew Chaikin’s book “A Man on the Moon” goes into some detail on this.
I couldn’t be any earlier than Apollo 4 since that was the first mission after the complete rebuild of the CSM after the Apollo 1 fire. I would put it at Apollo 6. There were major issues that needed to be resolved but the test was a success and NASA decided to forego further unmanned tests and so put astronauts on Apollo 7.
The way the Earth is coated with a uniform surface of solid rock?
Dust on the surface of a moon or plant isn’t subjected to much in the way of compression, since there’s little/no weight on top of it. If you want to turn that dust into a solid mass, you need tectonic activity to drag that stuff down to the depths, where it can get a nice warm hug (and bring up solid rock in its place). I don’t know what was known at the time of the Apollo missions regarding lunar tectonics.
The mechanical nature of dust also dictates the degree of its stability when subjected to uneven compressive loads from above. Imagine for example a tub full of small lightweight plastic spheres, each with a smooth surface; their low density and ability to slide past each other mean that if you try to stand on the surface, your foot will sink in. Imagine instead a tub full of crushed gravel; their high density and ability to lock together mean you won’t sink in when you try to stand on it.
Or the heat and pressure of significant impacts. (The smaller impacts just pound the regolith breccias back into regolith again.)
No, the earth IS solid rock (some melted as magma) – over 99% of the planet. It’s the thin coating that is non-rock: dust & soil & water & plants & animals.
So why are you surprised that other worlds/moons have a thin coat of broken rock on the surface, too?
(I see this doesn’t give a preview box—it is about former ideas on dust accumulation on the moon.)
http://apps.usd.edu/esci/creation/age/content/creationist_clocks/moon_dust.html
I’d like to see a cite also. Not only have I never heard that, the immune system explanation makes no sense. If we go by that reasoning, everyone who had to walk out of Ukraine in the last month while being shelled should have been quarantined because of the stress.
Sorry, can’t find the cite, but I read that the stability of the lunar surface WAS a concern, hence the large dish-shaped feet on the Lunar Excursion Module. And - if there was another mission, the updated LEM would just have skids like a helicopter.
Furthermore, if stress of going beyond the Van Allen Belts was that significant, they’d have quarantined the crews of Apollo 8 and 10.
Personally, I always thought the quarantining was extreme overkill. The Moon is pretty obviously deader than a doornail and the chances of them bringing back some horrible disease were so close to zero as to make no difference. It was just a waste of money to even have the module there at all.
They stopped quarantining Apollo astronauts after Apollo 14. If stress was a factor, the practice would have continued with 15-17.
I agree, the stress explanation seems to make no sense. I very rarely call for cites, but in a forum that has factual right in the name, people shouldn’t just drop unsupported statements of “facts” into the middle of a thread. Even worse, he was correcting someone that appears to be right.
Since he doesn’t seem to be following this thread, I’ll @Chronos him and see if he will drop back in.
I’ve been following it, but all the cite I can provide is the good old “I heard it somewhere”, which I didn’t think was worth posting for. I was hoping that someone else had heard it, too, but remembered where they’d heard it. It doesn’t look, though, like that’s the case.
If you start to google, by the time you reach “Why did apoll” it is already suggesting questions about the quarantine. There are tons of links, but how about straight from the space-horse’s mouth?
https://www.nasa.gov/feature/50-years-ago-apollo-11-astronauts-leave-quarantine
It was moonbugs.
Cheese mites, perhaps?
It wasn’t so much that there were cheese mites, we already had those. It was specifically “green cheese mites” we were worried about. Once it was discovered that Galactus was extremely allergic to them, we dropped the quarantine and let them thrive on Earth. Now we have no worries about Galactus eating our planet for it’s cosmic energy. And now you know how the Apollo missions saved mankind.
Well, Armstrong was considering going for aborted landing, as he was hunting for a safe place to land, so the very last danger was the risk of landing on an unstable surface… on a rock that was too uneven or loose and it tips the eagle over, eg one side on a tall rock ? or one side on rock and the other in dust ? and if it was deep dust it might sink in too deep.
But I guess the question means the last thing resolved on earth. The issues that occurred during the apollo 11 were accepted risks. Which risk did they mitigate last ?
One delay was the lunar lander training module LTTV-1 had been crashed, and LTTV-2 and 3 were grounded while the causes were resolved. I didnt find out what was the cause but they were on a tight schedule to get Armstrong trained in flying the lunar lander in the month before apollo 11 lifted off. see https://www.nasa.gov/feature/50-years-ago-apollo-11-preparations-march-1969
Everything else is “yeah well we have a manual for that, so its the ability to understand the manual that is being tested”. Lunar landing is a skill , they have to be sure he is skilled at it… as indeed he had to demonstrate proficiency for landing of the Eagle … it wasnt like he could say “turned out to be easier than we thought.:”
Interestingly, Armstrong was the one who crashed the test lander.