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23
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7 answers
Unix Epoch in International Space Station
The International Space Station is in a different gravitational field than us on the Earth's surface. Almost all computers / protocols depend on the Unix epoch being consistent everywhere. The Unix epoch is same for all computers on the Earth's…
exifguy
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How much of the energy of a rocket ends up as a noise?
Rocket launches are notoriously loud. So much so that measures are taken to prevent the noise/vibrations from damaging the rocket, the pad, or basically anything else within a few hundred meters.
How much actual energy is carried away in that noise?…
Steve Linton
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Why isn't SpaceX constructing the Super Heavy launch mount on top of the water?
With SpaceX creating their launch facility in Boca Chica Texas, right next to the water, why would they bother building a huge launch pad to withstand the blast, as opposed to building it on top of the water? Why not let 20 feet of water handle the…
David
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Was the Space Shuttle always crewed?
Maybe this question sounds snaive to some educated people, but I'm not clear if the Space Shuttle could and was ever used without a crew.
And what was the smallest and the biggest crew size it ever flown?
Joe Jobs
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Why is Elon Musk building the Starship first?
I mean what is he going to do with the ship alone? Is it even capable of orbital flight on its own?
Now the booster can be put to use immediately, and will probably be easier to make by far (I think)? Although, seeing how much use falcon heavy has…
Nikolai Frolov
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If rocket engines only need fuel and oxidizer, then why there are so many pipe lines on the engines?
If fuel and oxidizer are pumped by turbines to the combustion chamber, then why there are so many pipes around? It should only have a two-cylinder shaped turbine assembly. I doubt there are other gases also pushed in other than fuel and oxidizer.
Aarav Prasad
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Could Mars Rovers be lighter or faster if they didn't have to be tested on Earth?
Watching this video of Perserverance being tested on Earth, it occurred to me that requiring it to stand, drive, climb, etc. under 1g is, in some sense, overkill. Could this (or other) rovers be made more capable or less massy if it was not required…
Steve Linton
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23
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3 answers
What equipment was taken from Earth to the surface of the Moon and back?
During the Apollo missions, basically everything was left behind as soon as it was no longer needed. Of the approximately 45-48 tons that the CSM+LM weighed at launch, only 10% made it back to Earth. Most of this was the command module, which did…
Ludo
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4 answers
Why is NASA building its own rocket for the moon mission when it could use SpaceX's?
I read in this article that NASA is building its own rocket for the moon mission.
Why would they build their outdated and inefficient rocket, when they could instead use a SpaceX rocket and use their time to help with that production or do other…
Outsider
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Why was Canberra able to listen to Voyager 2 but not talk to it?
The New York Times's When Voyager 2 Calls Home, Earth Soon Won’t Be Able to Answer explains that because Voyager 2's trajectory has taken it way below the ecliptic, of the three 70 meter dishes in the DSN only Canberra's can talk to it. So when it…
uhoh
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3 answers
Why would oxygen be stored as a super critical fluid?
Organic Marble just answered a question about Apollo 13 in terms of the storage of Oxygen, and posted some fascinating stuff, including the fact that Oxygen was stored as a super-critical fluid.
I was just wondering what the benefits of storing…
Magic Octopus Urn
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23
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2 answers
Is the mass of paint relevant in rocket design?
(Prompted by this answer):
Do the designers of large rockets* (have to) take the mass of the exterior paint into account?
If so, do we have examples of actual design changes/decisions based on this (and not on other paint properties like color/heat…
user10509
23
votes
2 answers
How did astronauts using rovers tell direction without compasses on the Moon?
I read that the astronauts who used Lunar rovers used heading indicators, which typically use compasses, for direction. How, on the Moon, did their equipment tell the direction of travel, presuming a compass made for earth would not work on the…
john doe
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Why does the Saturn V have standalone inter-stage rings?
Why are they not integral to the lower stages, e.g. like the Falcon 9? This applies not only to the ring between the first and second stage and also to the shoulder between the second and third stage.
Meatball Princess
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How did the Apollo guidance computer handle parity bit errors?
The following answers mention the use of parity bits in the Apollo guidance computer:
this answer to Bits per core for the different versions of the Apollo guidance computer core rope memory?
this answer to How did the Apollo computers evaluate…
uhoh
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