81 votes
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Why don't the Space Shuttle's tires explode in the vacuum of space?

Standard atmospheric pressure at sea-level Earth is just 14.696 psi. Compare that to 340 or 300 psi (23.14 and 20.42 amt, respectively). The difference in internal tire pressure in Earth's atmosphere ...
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  • 75.3k
29 votes
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Is water on Mars the same as Earth water?

Fundamentally, water is water. In its purest form, it is the same anywhere, except perhaps for the isotopes. However, one of the wonderful things about water is the fact that it's a good solvent, and ...
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  • 118k
26 votes
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What was this Ziploc bag used for on an Apollo 14 moonwalk?

That's not a Ziploc bag, but the retroreflector's dust cover. Here is a larger image of it removed:     And here's an image with the cover still attached to the retroreflector:  ...
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24 votes
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Why is the Angara rocket called eco-friendly?

When you compare the waste products of LOX/Kerosene vs hydrazine/MMDH/etc, it is actually not too terrible at full combustion. (End up with CO2 and water, or CO2, Ammonia, and water). However, if ...
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  • 76.4k
23 votes
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Could permanent self-sustaining biodomes be built on Mars?

There are no technological barriers, provided one is not too ideological about biospheres. In a comment on the question it is remarked that self-sustaining biodomes have not yet been successful on ...
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  • 4,133
14 votes
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Dangers of launching a nuclear thermal rocket

It's not dangerous. The core would never be operated on Earth, and so would not become radioactive like you're thinking. A nuclear reactor on Earth that has been in operation is extremely ...
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  • 57.5k
13 votes

Why don't the Space Shuttle's tires explode in the vacuum of space?

The wheel wells are not pressurized. As @Tildalwave says, pressurization wouldn't make much of a difference. The wheel wells are insulated to an extent: the wheel well doors are part of the Shuttle's ...
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  • 121k
12 votes

What was this Ziploc bag used for on an Apollo 14 moonwalk?

To answer the last part of your question: yes, it was normal to throw away stuff that was no longer needed. On Apollo 11 alone, the astronauts left behind more than 100 items, including four urine ...
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  • 121k
11 votes
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Decision Factors for using 100% $ O_2 $ cabin atmosphere in early US space program

Despite a higher risk of a fire, pure oxygen also has some advantages. First, the internal pressure of the vessel is only a fifth of a normal breathing mix, allowing less structural load on the hull ...
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11 votes
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Why are the EVA suits in the suitport (concept) exposed to the environment?

You answered that in your question. The basic notion described is often seen on Mars rover style suits as in this image from Wikipedia. The suit itself is the airlock. To go EVA, you climb into the ...
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  • 76.4k
11 votes

Can fish really live in microgravity without water?

Gills aren't purely for respiration. Fish constantly excrete ammonia and urea from their gills and without sufficient water to wash the waste away this would soon cause death, much like how too small ...
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  • 121
11 votes
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Choosing a specific region to live on Mars, how important will the degree of dust there be, compared with the availability of water?

Water is extremely useful on Mars. You can use it to generate oxygen directly via electrolysis and the hydrogen byproduct can be reacted with carbon dioxide to make even more water. We drink water. ...
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  • 1,072
10 votes

Why are the EVA suits in the suitport (concept) exposed to the environment?

You have to consider that this is a concept that is still under development. If the suitports will really be used (and I don't see why not, it solves many problems at the same time) on Mars, or ...
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  • 75.3k
8 votes
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Choosing thickness of a Whipple shield

This is an incredibly complex problem, so the only way I can think of usefully answering your question is by referring you to NASA's Micrometeoroid and Orbital Debris (MMOD) Shield Ballistic Limit ...
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  • 75.3k
7 votes
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What kind of lighting does the ISS use?

Feng Shui is not used. The ISS is a science lab and Feng Shui is not scientific. Currently, fluorescent lighting is used. A study is underway to replace this with LED lighting. The Testing Solid ...
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  • 121k
7 votes
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How cryogenic oxygen was heated up for CM cabin repressurization?

Unsurprisingly, it worked exactly like it did in shuttle. To assure uniform flow, the capillary restrictors are coiled around a warm water-glycol line to increase the oxygen temperature. Page 2....
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7 votes
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When was an operational satellite accidentally damaged by another man-made object in space?

I think that there must be many such collisions that occurred without even the satellite operators noticing, and certainly not reporting them. There were also intentional collisions with anti-...
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  • 5,742
6 votes

Will suits worn on Mars lose kilograms of "expendable water" each time they are used?

Since Steve just contributed an answer to this...well, so will I. There's no need to consume and eject mass for heat control. Mars is cold. See, for example, this Science article. Although wind ...
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  • 4,496
6 votes

Temperatures in "near" space compared to LEO

A vacuum is a pretty good insulator, much better than the air at the altitudes balloons operate at.
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  • 121k
6 votes
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What happens in to the fuel in fuel-rich Lox-Kerosene?

TLDR: The combination burning of hot kerosene and sun-driven decomposition of any remainder gets rid of it quite quickly. From an environmental point of view, this is the bottom line: It is ...
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6 votes
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How to make a camera survive in (near) space?

I've used a stock GoPro on a high altitude balloon that made it to 40 km, it recorded the whole way up and down (on external power). So depending on your mass and financial budget you could use this ...
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6 votes

Why is there no concerted effort to collect solar energy on a global scale?

The scale needed to address human energy requirements in the near future and the scale of things like Dyson spheres are completely different. Human energy usage at present is about 18TW Assuming 20% ...
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  • 18.9k
5 votes

Will suits worn on Mars lose kilograms of "expendable water" each time they are used?

As far as I know, no Mars suit has been finalized yet. The Apollo A7L suit is really heavy (91 kg), which was acceptable in the Moon's lower gravity. On Mars it'd get uncomfortable pretty soon, so I ...
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  • 121k
5 votes

Will suits worn on Mars lose kilograms of "expendable water" each time they are used?

Well, of course we don't know what our engineers will choose but: Mars has an atmosphere so traditional earth cooling/heating is possible. Think about a fancy heatsink running in your MarsSuit.
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5 votes
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Determine envelopes for the payloads?

For STS payload induced enviroments, grab yourself a copy of the Space Shuttle User's Handbook and you will find plenty of data starting on page 31 of the pdf. Vibration, noise, thermal, pressure (...
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4 votes

Where can I breathe for free?

A colony on one of Jupiter's moons, say Europa or Callisto, could have a rocket fuel extraction industry that yielded cheap oxygen as a byproduct. You'd mine ice, melt it, and electrolyze it into H₂ ...
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4 votes
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Which computer monitors will work on Mars?

I think LCDs are going to be just fine on Mars. We have LCD displays meant to withstand temperatures as low as -50°C here on earth. Usually the displays do not work at such temperatures, though, so a ...
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4 votes

Does the ISS need more heating or more cooling?

In general, spacecraft have two issues with temperature: Getting rid of heat Thermal cycling In space, no one can hear you cry? Nor can they see you sweat. The equipment onboard the station has ...
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  • 76.4k
3 votes

Combating negative effects of space

I think one of the important things to consider about artificial gravity, especially in deep space, is the impact of thrust. Since, especially on interstellar, rockets could be expected to be ...
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  • 237
3 votes

How plans for Mars colonization comply with Planetary protection act?

First of all, it's doubtful that decontamination procedures on US rovers landed thus far were even completely effective, and let's not talk about the Russians. That aside, I think the answer to your ...
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