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1500 questions
18
votes
1 answer
Why explore Ceres?
The multi-target orbiter Dawn spacecraft, launched in 2007, is now approaching the dwarf planet Ceres and had recently sent high resolution images of Ceres from a distance of 46,000 km.
What is so interesting about Ceres that we decided to send a…
user3339411
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3 answers
Are there any theoretical size limits of man-made space stations/structures?
The question speaks for itself. If the answer is "yes", what are the problems in creating a large-scale space structure, maybe even dozens of kilometres large? What about moving & repositioning, building, handling, supplying, maintaining and…
Zoltán Schmidt
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18
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1 answer
Why is the Russian approach to the aerodynamics of their rockets different?
Russian rockets look like this:
They flare them out at the bottom. With their newest rocket, the Proton, the flared shape is gone but the boosters still have caps that angle in towards the main rocket so the shapes fuse together. American rockets…
kim holder
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18
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1 answer
What control engineering techniques are used for the landing maneuvers of Falcon 9-R?
Which are the main control theories behind the landing maneuvers of the Falcon 9? For the hovering part, as it approaches the landing surface, I guess the inverted pendulum control approaches would do it. But what about the control from stage…
KonstantinosV
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18
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2 answers
Is it more efficient to assemble spacecraft in orbit, or assemble on the ground and launch?
My friends and I were trying to figure this out a while ago.
I was thinking that by transporting smaller pieces into space via a lighter re-entry spacecraft, there would be overall less fuel used because there would be less "feedback" (ie more fuel…
JKor
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2 answers
How will SpaceX achieve landing of the Falcon 9 first stage?
What mechanisms and technologies will be used to control the descent and movement of the falcon 9 rocket's booster stage on its way to the landing pad?
Phizzy
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4 answers
How would swimming on Mars feel, given the lower gravity?
The hypothetical swimming pool is inside a habitat at atmospheric pressure, and on Mars at 0.38g of Earth. What are the major differences regarding water properties (viscosity, surface tension, cohesion, does it feel like gel...) and how would the…
drandrul
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18
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1 answer
What’s the story behind the Armstrong shoe phone gag?
What’s the story behind the shoe phone gag:
One internet source labels it as “Neil Armstrong and David Scott with their Gemini 8 shoe phone gag… the tag reads Emergency Communication earphone”.…
Woody
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18
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2 answers
Why multiple lightning towers at launch sites?
Here is a picture of LC-40 at the Cape. The four tall towers are basically lightning rods. Why are four required? Wouldn't one be sufficient?
Erik
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1 answer
Person falling from space
A person at rest 500 km above the Earth falls straight downwards. She has a snug magical force field around her that is totally rigid and completely protects her from outside heat. The force field does not change the shape of her body and DOES NOT…
CapIsland
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2 answers
Why haven't we sent seeds of life to other planets yet?
We could have sent seeds of life (say a few ounces of microbes) along with every planetary exploration craft. Why we haven't done that so far?
jorel
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2 answers
Could an Apollo astronaut have put their foot through the hull of the LEM?
In this interview (part of the extra material from the Apollo 13 film), Tom Kelly of Grumman talks about the construction of the Apollo LEM. In particular he mentions that the "skin" of the LEM was made of 0.012" aluminum and that "You could easily,…
ForgeMonkey
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1 answer
Why is the UKSA not called the Ministry of Space?
As far as I know, most agencies in His Majesty's Government have a name in the format Ministry of Xyz. However, the space agency is called the UK Space Agency (UKSA). Why?
Is it a case of copying the Americans, was the acronym MoS already taken,…
Infinite_Maelstrom
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2 answers
What kind of heating would occur during a suborbital re-entry?
What kinds of peak temperatures would a stage similar in proportions to the Space shuttle with a similar belly-first approach experience when re-entering from a low suborbital trajectory (similar to a first stage)? Would this necessitate heat…
XBN
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18
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6 answers
Why aren't there any space tugs in use?
Ion thrusters are capable of providing the same amount of delta-V for far less fuel (e.g. Falcon 9 v1.1 second stage specific impulse is 340 seconds, while some ion-thrusters have a specific impulse of over 10000 seconds).
Ion thrusters have…
user6738