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197 votes
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Nudism in space: Why wear clothes anyway?

Clothes require laundry because they have accumulated dirt and other materials from the environment and their wearer. If the astronaut was not wearing those clothes then that material they captured ...
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85 votes

Nudism in space: Why wear clothes anyway?

Clothing performs essential duties on the station in addition to modesty. They are an easy way to organize stuff. In addition to pockets, clothing is festooned with velcro strips for attaching tools, ...
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56 votes
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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 ...
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43 votes
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Can/should you swim in zero G?

Two major problems present themselves right away. As the human body is almost neutrally bouyant with water, one might think that there are no issues with the actual movement in water. But this is only ...
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38 votes
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Can you take a bath on Mars?

Short answer, No different from Earth in floating. Buoyancy in water or any fluid is based on the weight of water displaced. Floating is based on the weight of the item displacing water. This is ...
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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 ...
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  • 6,903
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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29 votes

Is there any economical way to move the water from the Martian poles to the people?

You don't care about transporting H₂O. You want to transport hydrogen and oxygen atoms, and if that includes a few other atoms as baggage, that's no big deal. One easily available atom is carbon, as ...
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  • 1,604
28 votes

What does space have to do with providing "fresh water ... without the need for aquifers or pipes?" as Steven Kwast suggested?

The speech is available in full here: https://dc.hillsdale.edu/News/Latest-News/The-Urgent-Need-for-a-U-S-Space-Force/ It's extremely general and non-technical. He talks about getting water from the ...
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26 votes

Nudism in space: Why wear clothes anyway?

In addition to capture of contaminants, such as dead skin, hair, sweat, etc, and abrasion/cut protection, clothing forms a basic thermal layer that allows the human body to better regulate its ...
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  • 1,093
23 votes

What is the difference between an astronaut in the ISS and a freediver in perfect neutral buoyancy?

An astronaut practicing an EVA in the Neutral Buoyancy Laboratory (a large swimming-pool like facility) is still affected by gravity. They are pulled down relative to the suit - which is buoyed up by ...
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22 votes
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What is the difference between an astronaut in the ISS and a freediver in perfect neutral buoyancy?

A freediver could not be in perfect neutral buoyancy. The air in his lungs causes his chest to be more buoyant than his legs. So he would be turned chest up, legs down. Been there, done that. If you ...
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21 votes
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How do space capsules float on water?

Capsules like Apollo and Orion are mainly open space internally (the crew cabin); they have no problem floating by themselves (like a metal-hulled boat would). The conical capsule shape by itself ...
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19 votes
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Why was it necessary to monitor the water quantity in the space shuttle?

Water was used for many purposes in the shuttle. The particular application you are asking about is the Water Spray Boiler (WSB), part of the Auxiliary Power Unit / Hydraulic (APU/Hyd) system. This ...
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17 votes

Nudism in space: Why wear clothes anyway?

A picture might be worth a thousand words. Just imagine this situation without clothes:
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16 votes
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How would swimming on Mars feel, given the lower gravity?

Shortly after this question was asked, it was answered (in the case of the moon, not Mars) on XKCD's what-if. Summarizing that article, for most average people swimming would be the same, as the ...
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  • 6,553
16 votes
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What is the science behind the canals of Mars?

Canals on Mars has quite an interesting history, starting with Giovanni Schiaparell. He produced this map of Mars in 1877 It is interesting to compare this map to a more modern map Note that the ...
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16 votes
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What does flying in Enceladus's plume accomplish?

Cassini's INMS, the Ion Neutral Mass Spectrometer, is an in situ instrument that measures the neutral and plasma gas composition of what it ingests. It was intended for the measurement of Titan's ...
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16 votes
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Will uncovering the ice deposit in Utopia Planitia improve the climate on Mars?

Well, let's see how we can try to calculate that. First of, we need to find out what is the mass of the column of air on Mars and then find out how much mass the sublimation of ice will add to it and ...
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16 votes

What is the difference between an astronaut in the ISS and a freediver in perfect neutral buoyancy?

The viscosity of the surrounding medium has a lot of impact concerning your ability to move. If, for some reason, your body starts rotating, you'll come to a rest quickly in water, but it'll take a ...
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16 votes

Earth Launch System with Water Propellant

Electrolysis-based propulsion becomes practical only once you've reached orbit, where you can power the electrolysis with solar panels and where you don't need enormous thrust. Whatever you'd use to ...
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15 votes

Why can't plants grow on Mars?

Plants don't just need carbon dioxide; like most organisms, they need oxygen to survive as well. They can produce oxygen from carbon dioxide, but that doesn't help cells that aren't exposed to ...
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13 votes
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What about gathering water ice from Saturn's rings?

For a Hohmann transfer to Saturn, I get 15.7 km/s for both burns. The transfer time is also a simple formula. I obtain roughly 6 years. Compare to the lunar ice. It is roughly 2.8 km/s to get to, and ...
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  • 16k
13 votes

Is there any economical way to move the water from the Martian poles to the people?

Canals? It's too cold on Mars for water to be liquid, so canals are not going to work. Pipes? ...would need to be constantly heated, so they would require quite a lot of energy. Hydrogen ...
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13 votes
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What does space have to do with providing "fresh water ... without the need for aquifers or pipes?" as Steven Kwast suggested?

The article says that the page has been adapted from Kwast's speech, so it's possible someone transcribed something wrong or misunderstood. Taking an excerpt: With the right vision and strategy for ...
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12 votes

How would swimming on Mars feel, given the lower gravity?

TLDR Its much harder to swim fast, even though it might be easier to swim slowly. WHY Your main difference will be due to a reduced hull speed of the swimmer. As noted in the comments section, the ...
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12 votes
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Boiling ponds and pools on Mars?

The other answers forget latent heat/enthalpy of phase change, and many neglect pressure rise with column of water. :) Enthalpy of evaporation of liquid water is considerably higher than its latent ...
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12 votes
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Could a ball of water stay in orbit?

The ball of water in that picture is in orbit; it's just surrounded by (presumably) the ISS. But a ball of water like that definitely cannot survive in the vacuum of space. Below a certain pressure, ...
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  • 6,903
12 votes

More water in a crater on Mars than the quantity dumped by the river Nile into the Mediterranean sea in 45 years?

The ice-filled Korolev crater appears in Viking imagery taken in the '70s. It took the arrival of suitable radars in orbit (like MARSIS on Mars Express and SHARAD on MRO, ca. 2005-6) to determine the ...
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12 votes

Can/should you swim in zero G?

Off the top of my head, two issues for free swimming (no breathing gear) I can think of: Absent a sense of "up" and "down", it would be very easy to become disoriented and lose track of where the ...
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