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1500 questions
42
votes
3 answers
Why did NASA use U.S customary units?
NASA was using U.S customary units (inches, feet, nautical miles, pounds, tons, US gallons etc.) during the Mercury and Apollo programmes, and beyond.
There are significant disadvantages to using U.S customary units, the most obvious being that the…
user
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42
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2 answers
Was planting UN flag on Moon ever discussed?
In the planning of the US missions to the moon was planting the UN flag ever discussed? It just seems to me that would have been a great public relations move.
MaxW
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42
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5 answers
Why are so many space telescopes placed in LEO instead of at Lagrange Points? And why do we hear about Hubble more than any Langrange-orbit telescope?
Here is the list of every space telescope launched by different space agencies - List of space telescopes. Most of the listed telescopes are placed in Lower Earth Orbit (about 95% of them). It's probably not an ideal location to place a telescope…
Paran
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42
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2 answers
What is that haze on Starman's windshield?
There is a haze on the top half of Starman's windshield? It was not there in the first day o fthe launch and the video feed. It looks like fogged window, but assume it cannot be that. What is it and how did it form?
kdobrev
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42
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1 answer
Do booster stages run out of fuel, or are they purposefully shut off?
When an expendable booster rocket stage nears the end of its burn, does the guidance computer shut the engine(s) off at a certain velocity/altitude for the mission, or does the stage completely exhaust its propellants?
Jake Blocker
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42
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5 answers
Why aren't we sending quadcopters to mars?
After watching the MARS series on National Geographic I noticed that they sent one of their crew members down a chasm to check for ice. I wondered, why they did not just take a regular commercial drone with them and explore the chasm with…
Thomas Wagenaar
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42
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3 answers
Have we attempted to experimentally confirm gravitational time dilation?
Mark Adler wrote in an answer to a different question that
We would expect that Voyager 1's local time is faster than Earth time by about one part in one hundred million.
I don't think that the Voyager oscillator is stable enough to measure that…
user
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41
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7 answers
Why are we trying to prevent life from spreading via landers rather than actively encouraging it?
The question How certain are we that we have not accidentally sent life to other planets/moons? talks about all the precautions taken to avoid spreading life to other planets/moons. But why even try it? Wouldn't we want to actively spread bacteria…
JonathanReez
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41
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6 answers
How does GPS receiver synchronize time with GPS satellites?
GPS satellites transmit time values regularly, but if we put in consideration the time delay between the satellite and the receiver, the time value received wouldn't be accurate insofar as I know GPS receivers aren't able to determine their position…
digiogi
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41
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5 answers
Why did the SpaceX Starship SN10 explode?
Much to everyone's relief.
The SpaceX Starship SN10 successfully completed its flight and landed.....
But, sometime later, It exploded!
Why?
And did it have anything to do with the fire near the Raptor engines?
Đαrkraι
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41
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4 answers
Why did multiple nations decide to launch Mars projects at exactly the same time?
There seem to be multiple Mars projects all happening at around the same time:
The Emirates Mars Mission was the first of the three to arrive at Mars on 9 February 2021.
Tianwen-1, an interplanetary mission by the China National Space…
nycynik
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41
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3 answers
Why haven't more spacecraft/satellites been hit by debris?
It is touted by the media that space is becoming more dangerous and risky due to an increase in space debris. Why haven't more craft been hit by the debris? I presume that it is not at a critical level yet. Do the space agencies have avoidance…
Marmstrong
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41
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6 answers
Does a satellite naturally turn in phase with its orbit, always facing Earth?
Assume you want a satellite to constantly point its radio dish towards Earth while orbiting it, or its solar panels towards the Sun if it is instead orbiting it. Is any of the following true about what is needed to achieve this?
continuous change…
LocalFluff
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41
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2 answers
Are there foods that astronauts are explicitly never allowed to eat?
Is any substance strictly forbidden for astronauts in space, because it may dehydrate, cause intestinal problems or other ailments/threats to systems if improperly handled? Anything someone may ingest is valid for an answer- drinks included. (Asking…
Magic Octopus Urn
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41
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5 answers
Where does space begin on planets without atmospheres?
On Earth the Karman Line is used as the boundary of space, and I believe it is defined as the height where you would have to go faster than orbital speed in order to obtain aerodynamic lift. Therefore planets like Mars and Venus also have Karman…
TeslaK20
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