Questions tagged [ammonia]

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Using coolant as 3rd propellant

Rocket engines often have 2 propelants, one of which is used to cool the engine and after that the hot propellant is injected in the combustion chamber. Would make sense to have a third propellant ...
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2 votes
0 answers
41 views

Prop feed with Anhydrous Ammonia in Microgravity

Considering contributing to an SBIR through my PhD where we're looking at NH3 as a green prop solution. Need to figure out how to feed vapor from a liquid/mixed phase tank to the a prop system. ...
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11 votes
1 answer
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What is a K-bottle?

This answer has pictures of the Enterprise shuttle, which was used for gliding and landing tests. One picture (included below) shows oxygen, hydrogen, and ammonia stored in "K-bottles". ...
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3 votes
1 answer
178 views

Why would it be "less bad" for hydroxylammonium nitrate monopropellant to freeze than for hydrazine?

Answers to Is it bad if hydrazine freezes on a spacecraft? Is it always kept as liquid, or can it be safely allowed to freeze and then thawed when needed? explain that while the freezing of hydrazine ...
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4 votes
1 answer
1k views

Why do the ISS' Thermal Rotary Radiators need to tilt?

This answer shows the first image below of a vintage view of the ISS. Only one of each triplet of thermal radiators is extended from each TRRJ. The ISS' solar panels articulate to modulate the ...
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3 votes
1 answer
108 views

Selection criteria for coolant media on spaceships

What is the selection criteria for coolant media on spaceships? I have read that ammonia as well as water glycol have been used. These two have very diverse properties. So what makes both of them ...
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6 votes
1 answer
273 views

Why is hydrazine used in arcjet thrusters?

Most arcjet thrusters seem to use hydrazine or ammonia, with some research being done on hydrogen and water arcjets. I know hydrazine is easily catalyzed into exothermic decomposition, and it and its ...
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24 votes
5 answers
8k views

Reasons why liquid anhydrous ammonia fuel chosen for the X-15? Has it been used in other rocket engines?

Both Flight 90 and Flight 91 of the North American X-15 crossed the Kármán line, reaching altitudes of 106.01 and 107.96 km respectively. Both flights were piloted by Joseph A. Walker, who became in ...
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1 vote
0 answers
306 views

Ammonia synthesis on Mars — has there been any discussion or research?

Ammonia can be used in the production of fertilizer, as a source for nitrogen in soil for plants, in this case for food. Synthesis of ammonia from nitrogen can be done with the help of bacteria using ...
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  • 111
4 votes
3 answers
964 views

Is HAN-water propellant "green" enough to ever be used in a cubesat?

I just read about the "green" propellant Hydroxylammonium nitrate writing this answer. It will be tested in the Green Propellant Infusion Mission (also see GPIM AF-M315E Propulsion System). Catalytic ...
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7 votes
4 answers
2k views

What kind of engine does this Isp = 1600 refer to? Is it cubesat-friendly?

These two good answers (one and two) to the question "Is there a maximum Isp for 'exothermic chemical reaction rockets?'" put the limits around 500-550 seconds for the limits of practical ...
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8 votes
1 answer
395 views

Why does Jupiter have the colors it does?

This was sparked by an interesting conversation in the chatroom. We were discussing how Jupiter, being made of gas, has a lot of color. Looking into it, I found this statement, from Universe Today: ...
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19 votes
1 answer
608 views

Are there any promising next-generation space station cooling technologies?

The ISS had problems related to ammonia more than once. These problems happened in different calender years, and it seems like almost every "near miss" that makes the news about the ISS is connected ...
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8 votes
1 answer
338 views

How does Bigelow plan to handle heat rejection on the BA-330?

Bigelow Aerospace has two inflatables on orbit (Genesis I and Genesis II) with plans for attaching the BEAM module to the ISS. These are precursors to a full scale station, based on multiple (3?) BA-...
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