Questions tagged [pressure]

Pressure is the force applied perpendicular to the surface of an object per unit area over which that force is distributed.

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How could the 2018-08-30 Soyuz MS-09 / ISS leak be so slow?

The leak reportedly led the ISS to lose 0.8 millibars of air pressure per hour, which is both big considering what was at stake and low for a 2-mm hole when the outside is near to complete vacuum. Am ...
tsnobip's user avatar
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3 votes
1 answer
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Temperature and pressure of rocket exhaust

What is the temperature and pressure of the exhaust that comes out of the rocket during the last three seconds of countdown (smoke that stays near ground)? How much carbon dioxide is there in that ...
carolin's user avatar
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12 votes
4 answers
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Why do pressure-fed systems have to be pressurized with helium or nitrogen?

This is something I just don't understand. The way I see it, propellant can be pressurized all on its own in the tank. Just pump a lot of the stuff in there and make sure the tank is strong enough. ...
DrZ214's user avatar
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14 votes
5 answers
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Why do pump and pressure fed liquid engines need to operate at high pressures?

There is apparently some confusion as to why pump or pressure fed liquid rocket engines need to operate at high pressure to product significant thrust, based on the comments to this question about ...
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9 votes
2 answers
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What is the deepest place on Mars? Do humans need pressurized suits there?

Is there any particular deep area, trench, fissure, lava tube or otherwise on of Mars in which a person could survive with only an oxygen supply? How deep would plants or animals have to be in Mars ...
Muze's user avatar
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7 votes
1 answer
3k views

How does the chamber pressure affect the performance of a Rocket Engine?

I am under the assumption that higher chamber pressure results in increase in exhaust velocity. Is this true?
user28833's user avatar
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2 votes
1 answer
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Chamber pressure of a gas pressure fed liquid rocket motor

I am studying rocketry and am currently learning about pump fed vs gas pressure fed propulsion systems. Upon reading about gas pressure systems, I googled the formula to find the chamber pressure for ...
Dylan Meiners's user avatar
0 votes
1 answer
331 views

Ambient pressure for vaccum nozzle design

How do I find out the ambient pressure for designing a vaccum rocket engine? I am using the propellant combustion charts from the braeunig website. But I cannot figure out the ambient pressure for ...
user167195's user avatar
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1 answer
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why do under-expanded engines have less than ideal thrust?

I've been looking into rocket propulsion a bit and got stumped on something. I read that the thrust generated by an engine can be determined by the following: $$ F = \frac{w}{g}v_{e}+A_{e}(P_{e}-P_{a})...
Ben Woodman's user avatar
10 votes
3 answers
5k views

When staying indoors, can missing gravity be replaced with blowing air?

As I was watching Ad Astra (Great movie, but where does the gravity come from?), I had the idea that in a building or closed vehicle in a low gravity location, maybe air pressure could be used to ...
Antti Rytsölä's user avatar
6 votes
1 answer
469 views

What effects did the different air pressure and air composition in certain spacecraft have on astronauts?

The Mercury and Gemini spacecraft, and in space the Apollo spacecraft, didn't pressurize their cockpits to 1 atm with Earth-like atmospheric composition; instead, they used pure oxygen at much lower ...
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6 votes
2 answers
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Does chamber pressure have the same impact on ISP for different types of engines?

From this answer I understand that higher chamber pressure means higher ISP - but is this always the case for similar engines? For example: I noticed that a lot of upper-stage engines have pretty low ...
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4 votes
3 answers
302 views

How to read this Cassini Main Engine Operating Box (oxidizer vs fuel tank pressures)?

The extremely cool NASA JPL video Triumph at Saturn (Part I) is really worth a watch and/or listen. At about 34:32 it covers the period just before SOI (Saturn ...
uhoh's user avatar
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1 vote
0 answers
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How does temperature affect a solar sail?

Is there an ideal temperature which solar sail material operates at? Does a colder reflective surface create more thrust? Related: How will JWST manage solar pressure effects to maintain attitude and ...
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