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1500 questions
57
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How does the Falcon 9 first stage avoid burning up on re-entry?
Now that a Falcon 9 first stage has successfully landed after a launch mission, I want to know how the first stage can avoid burning up when coming back down to earth.
There doesn't appear to be any heat shield on the bottom of the rocket, and I…
Rickest Rick
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Why did NASA send two astronauts to the moon instead of one?
I can think of a lot of good reasons for both arguments, and the Soviets made the opposite call for their lander, but what I'm interested in here is this:
Given the mass penalty of another man (body weight, supplies, oxygen, propellant) and given…
Dave Markle
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How did Canada come to be the robotic arm people?
Canada contributed the Canadarm and Canadarm2 for the Shuttle and ISS, respectively. With the Lunar Gateway Canada will contribute the Canadarm3. How did Canada come to make the Canadarm in the first place? Do they continue to just because it's…
shabuki
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Why doesn't the Falcon-9 first stage use three legs to land?
The immediate thought that would probably come into your mind would be "Because 4 legs is more stable than 3." However that is not always true. 3 legs offer the same or in some cases more stability as 4 legs as 3 legs guarantee they are in the same…
Star Man
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56
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1 answer
Why use water tanks from a retired Space Shuttle?
In 2015, technicians entered the retired Space Shuttle Endeavour to remove the water tanks, with the goal of reusing these tanks on ISS.
The space shuttle Endeavour is retired and on display at the California Science Center, but it's still…
Nightrider
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What technological breakthroughs were required to land booster stages?
It is only recently that SpaceX developed first stages that can land again, and be reused.
The (until recent) non-existent landing of re-useable rockets is presumably, partially, due to a lack of will (the Apollo program did not care about reusing…
Wouter
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Can a miniature Saturn V get to the moon and back?
If the Saturn V rocket along with its Apollo spacecraft was miniaturized, for example to 1/72 scale so it was five feet tall, could it still perform a moon landing like the Apollo missions and get back to Earth? The rocket equation only involves the…
Thomas
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2 answers
Why are we trying to build a base on Mars before the Moon?
My question is very close to the question answered in the link below and is raised by the answers that question received:
Is a Moon-base inherently more dangerous than a Space Station?
Why are we struggling to get to Mars prior to building…
James Kolar
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4 answers
What impact will the deorbiting of thousands of satellites have on the atmosphere?
With the creation of mega satellite constellations like Starlink, there are several thousand satellites being launched each year. This means that as these satellites go out of order in a few years, there will be thousands of satellites being…
usernumber
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This image of the Space Shuttle is truly beautiful, but is it real?
I saw this image in the Infobae article La NASA probará un paracaídas para posar naves espaciales en Marte ("NASA will test a parachute to place spaceships on Mars").
The image looks plausible to me, refraction in Earth's atmosphere, a crescent moon…
uhoh
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55
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4 answers
What was the fate of the main core of the first Falcon Heavy launch?
February 6th 2018 saw the first test launch of SpaceX's Falcon 9 Heavy rocket.
During the main core's landing on the marine landing pad, the connection was lost. As such it is not immediately clear whether the launch and landing were a complete…
JAD
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3 answers
Is 75 meters an exceptionally close distance for two satellites to pass at >6,000 m/s?
While researching for this question I ran across something called Celestrak Socrates. I requested the ten closest predicted approaches, and saw distances of closest approach of the order of 100 meters or even less. I recalled this question but this…
uhoh
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What is the purpose of the jets of water often under rocket engines during launch?
I have watched several STS launches, and noticed that there were always huge jets of water that would begin right before the rocket engines lit. They were right under the rocket, mounted to the pad.
I'm sure they weren't trying to extinguish the…
user12
54
votes
3 answers
Why did Voyager 2 receive a gravitational slowdown (as opposed to a slingshot) at Neptune?
I was actually answering this question today regarding velocities of spacecraft, and it occurred to me I've never really looked at this graph in much detail before:
Heliocentric velocity of Voyager 2 plotted against distance from the sun
As you can…
marked-down
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Why is gold used in space technology to protect from heat radiation?
AFAIK, NASA and others are using mainly gold to protect surfaces from heat radiation.
But, as we can see with our own eyes, chrome or silver had probably a much better albedo, because they are white, with very good reflectivity - eligible to make…
peterh
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