56
votes
Accepted
If an astronaut threw a cup of coffee into space, would it freeze, or boil off into gas?
This was tested nearly sixty years ago. Using a very large cup filled with 95 tons of water. An empty second stage of a Saturn I under test was used. Only the first stage should be tested but with ...
- 49.3k
55
votes
Why does there appear to be a 180-degree stereo microphone array outside the ISS?
That is a UHF antenna. It was well placed on the Lab to get in the way of robotics ops during space station assembly.
This is a picture of a different UHF antenna unit (this one is on the P1 truss ...
- 188k
36
votes
Could there be any use with importing vacuum from space to Earth?
There are multiple problems with this idea.
The first and most obvious problem is that the sealed container which has a perfect vacuum inside (seller claims so at least) is not of much use until you ...
- 1,841
36
votes
Accepted
Was the ship decompression scene in the movie Aliens realistic?
I did a quick extrapolation from Organic Marble's data (1.5" diameter hole = lose 1500 lbs of air per hour from 14.7 psi; flowrate proportional to the square root of the pressure differential) and my ...
- 170k
31
votes
If an astronaut threw a cup of coffee into space, would it freeze, or boil off into gas?
It would not freeze into a block. It would quickly expand and boil, but not in a rolling boil. Without pressure, bubbles would form throughout the coffee and expand rapidly, causing it to spray out of ...
- 11.4k
30
votes
What stages of distress occur to a person when there is a small hull breach in space?
To understand subjective symptoms of a hull breach, it is important to remember that respiratory drive (the sensation of shortness of breath) is driven by blood CO2 level, not blood O2 level. As long ...
- 24.8k
27
votes
Accepted
How come we don’t put a huge windmill-like machine in space?
As far as I understand you want the "windmill" to drive a dynamo. Have you ever tried turning a dynamo? It takes some force to do so, and that force is then (partially) turned into electricity. So the ...
- 12.6k
26
votes
Accepted
How are vacuum optimized engines tested without disintegrating them?
Flow separation can occur in a rocket nozzle that is overexpanded.
This can cause quite severe turbulence and thus buffeting of the rocket nozzle.
The SSME used a special rocket nozzle shape to ...
24
votes
Was the ship decompression scene in the movie Aliens realistic?
As much as I love this movie, it's not very realistic.
Here are some cabin leak numbers for the shuttle Orbiter.
At an initial 14.7 psi cabin atmosphere, a 1.5 inch diameter round hole was projected ...
- 188k
21
votes
Accepted
Can Maglev trains ever reach escape velocity?
What you are proposing is known as a mass driver, and the concept goes back at least to the 1960s. It was discussed by Gerard O'Neill in the 1970's as part of a method to build space colonies, and ...
- 11.4k
17
votes
Could there be any use with importing vacuum from space to Earth?
According to WP, at the upper end of Earth thermosphere -- that's LEO, somewhere above the orbit of ISS -- the pressure goes to around $1 \times 10^{-7}$ Pa.
This level of vacuum is regularly ...
- 170k
16
votes
Accepted
How do the roll-rings at the ISS work?
The ISS Utility Transfer Assemblies (UTAs) are located in the center of the Solar Alpha Rotary Joints (SARJs) - the continuously rotating interface between the outer truss segments that support the ...
- 188k
14
votes
Accepted
What is the ring at the bottom of the Merlin vacuum engine?
The nozzle of the Merlin Vacuum is very large, to help get better expansion ratios since it only ever fires in a vacuum, unlike the 9 sea level optimized Merlins that have smaller nozzles.
This is ...
- 80.2k
13
votes
How are vacuum optimized engines tested without disintegrating them?
There are several test stands with altitude capability of up to 100 K ft (30.5 km or 8 Torr) for engine firings using the steam
ejector system and up to 250 K ft (76 km) non-firing capability with ...
- 49.3k
13
votes
What stages of distress occur to a person when there is a small hull breach in space?
Supplementary answer
For your timeline, it's important to note that the pressure drop is not even remotely linear. The flow through the leak is large at first because the differential pressure is ...
- 188k
12
votes
Do electronics and mechanical components work in a vacuum or require a sealed controlled atmosphere?
Generally speaking, all "air-tight" containers leak to some small degree. On Earth this manifests itself as an inability to maintain a vacuum indefinitely; in space, it manifests itself as an ...
- 7,330
12
votes
How come we don’t put a huge windmill-like machine in space?
Consider the windmill as a system.
If there is no wind blowing on the windmill, there is no energy being
input into the system.
If you pull power out of the windmill, energy is being output from
the ...
- 188k
12
votes
Accepted
Would a spaceplane be able to softly land on an airless planet?
Yes But...
This only works if your craft can generate enough thrust to reduce orbital velocity to zero quickly enough that acceleration due to gravity does not produce a crash landing, since you are ...
- 23.4k
12
votes
Accepted
Does the Merlin vacuum engine on SpaceX's Falcon 9 gimbal?
According to the Falcon Payload User's Guide posted on the SpaceX website, the 2nd stage engine gimbals. (Emphasis mine)
- 188k
10
votes
In the absolute vacuum of Space, will an electric dynamo still work?
Unless the lubrication system fails in the dynamo that is in vacuum, electrical generation will work. Magnetic fields are unaffected by air or the lack of, at least at the level under consideration.
...
- 1,975
10
votes
Accepted
Are galvanised steel parts safe to use in space?
It's not just zinc. Pure tin coatings and cadmium coatings are also prohibited, at least in the vicinity of electronics. See the Prohibited Materials Section of the NASA Parts Selection List (NPSL).
...
- 75.5k
10
votes
Lorentz force space propulsion
The linked paper looks very bogus.
Electromagnetic propulsion by itself is nothing unusual. Pushing against the Earth's magnetic field or similar can very well be used to generate some mild thrust.
...
9
votes
near space vacuum balloon
But would it be possible to create one that floated near space with almost no air pressure?
Possibly, depending on what material(s) you use to make the balloon.
If so how much could it lift? what ...
- 2,598
9
votes
Accepted
Mars Vacuum-blimp Feasability
For the sake of this answer I'm going to use the numbers I get from NASA and Wolfram Alpha. These are:
...
- 294
9
votes
Accepted
Why were some early interplanetary probes pressurized?
This was done to simplify thermal management. In a pressurized container, you can use air cooling. In a vacuum, you have to use heat pipes or liquid cooling to transfer heat to a radiator.
This also ...
- 128k
9
votes
Accepted
How do you test-fire vacuum engines in a vacuum chamber? Why doesn't it fill up almost instantly from the exhaust and spray (deluge) water?
I got a book from 1963, "Wie funktioniert das?", how things work:
Translation:
...
- 49.3k
7
votes
Has any living thing been directly exposed to the vacuum of space
In 1964 and 1965 at Holloman Air Force base in New Mexico a number of chimpanzees were exposed to a vacuum for 30 seconds. They were at 2 mm of mercury, which is 0.038 psi. They were revived with pure ...
- 4,924
7
votes
Has any living thing been directly exposed to the vacuum of space
In 1996 in a vacuum chamber space suit test Jim le Blanc had his air hose detach and he was exposed to a virtual vacuum at 0.1 psi. It was 87 seconds before the chamber was returned to normal air ...
- 4,924
7
votes
Has any living thing been directly exposed to the vacuum of space
I'm pretty sure this hasn't happened to Humans...
Depends on your definition of 'exposed'...
Soyuz 11 suffered an accidental depressuriation when preparing for reentry, when a valve accidentaly ...
- 7,846
7
votes
Was the ship decompression scene in the movie Aliens realistic?
The outer door of the airlock should open inwards against the air pressure. But opening the door against the huge force of the pressure to the large area of the door is impossible.
If the door is ...
- 49.3k
Only top scored, non community-wiki answers of a minimum length are eligible