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Questions tagged [cryogenics]

Questions regarding use, design, storage, consumption, or other considerations of materials, propellants, systems, or biological samples stored and/or used under very low temperatures, often under larger than ambient pressure.

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33 votes
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What are the droplets/particles falling off rockets at launch?

In this picture from the AsiaSat 6 launch by Falcon 9 on 8th September 2014, the part of the rocket between the fairing and the engine appears to be surrounded by dust, water droplets or debris: And ...
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26 votes
4 answers
5k views

Does the NK-33 engine require subcooled kerosene so cold that it turns to wax?

It was mentioned in this answer and in several other places on the internet that the kerosene fuel used by NK-33 engines needed to be subcooled enough so that it reached the same density as the LOX, ...
uhoh's user avatar
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24 votes
3 answers
3k views

How are cryogenic rocket propellants delivered to the launch pad?

I work at a university that gets LN2/LHe (liquid nitrogen and helium) delivered a couple times a week by a large tanker truck outside my office. It seems to work well enough to deliver a couple tons ...
Nick T's user avatar
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22 votes
2 answers
2k views

Can I drink the water from the plumes of SSME?

Shuttle's SSME uses cryogenic Hydrogen(LHX) and Oxygen(LOX) as their propellent to give hot water vapour. If I somehow manage to get the exhaust plume and condense it to liquid, Can I drink it ...
Hash's user avatar
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20 votes
3 answers
5k views

How are fuel tanks filled with cryogenic hydrogen?

Cryogenic hydrogen can react with the atmospheric Oxygen to produce an explosion: as well as being cold enough to liquefy (and possibly solidify) atmospheric oxygen, which can be an explosion ...
Hash's user avatar
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18 votes
3 answers
4k views

How does SpaceX plan to deal with boiloff on the trip to Mars?

Both BFR (Big Falcon Rocket) booster and BFS (Big Falcon Spaceship) are to run on Raptor engines, fueled with liquid methane and liquid oxygen - cryofuels. The trip to Mars will take at least a couple ...
SF.'s user avatar
  • 55k
18 votes
2 answers
2k views

How big a weight problem is ice sticking to a rocket?

Cryo tanks are so cold, they tend to condense moisture out of the air, creating ice covering a lot of the rocket. I've seen many videos where this ice starts shedding at launch, but I still have to ...
DrZ214's user avatar
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17 votes
3 answers
3k views

In a cryogenic fuel rocket, at what pressure is the fuel injected into the engine?

The pressure in the Space Shuttle's main engines must be very high to get the vehicle off the ground (with the SRB assist, of course). With such high pressures inside the engine, how do you inject ...
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15 votes
1 answer
2k views

What is the advantage of using Helium over Nitrogen when used for pressurising LOx?

In this Twitter post of the plumbing line diagram(left half) by LauncherSpace, one can notice that Helium is used for pressurising LOx while Nitrogen is used for pressurising Kerosene. Why the ...
karthikeyan's user avatar
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15 votes
1 answer
4k views

How long is it feasible to store cryogenic fuels?

Working with liquid nitrogen all day, I am constantly bothered by their boiling away, forcing me to go get more from the storage dewar. Likewise should be the case with any cryogen, e.g. LH2 and LOX ...
Nick T's user avatar
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14 votes
1 answer
2k views

Changes made to ISRO GSLV-D5's CUS and FBTP since GSLV-D3's LH2/LOX CUS failure to sustain ignition?

The launch of the ISRO GSLV-D5 launching India's GSAT 14 advanced communications satellite (weighing 1,980 kg) is slated for 19th of August, 2013, flying in the GSLV Mk.2 configuration with an Indian-...
TildalWave's user avatar
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13 votes
1 answer
1k views

Why did SpaceX swap the LOX and CH4 tanks between Mk1 and SN1?

According to most sources, the Starship Mk.1 had its LOX main tank (not talking about the header tanks here) on top and its main methane tank below. But it seems the SN1 revision, and all subsequent ...
Piotr's user avatar
  • 131
12 votes
2 answers
2k views

Why was the Shuttle's LOX tank on top of the LH2 tank, since that makes it more top-heavy?

The external tank for the shuttle contained tanks of liquid Oxygen and Hydrogen for the main engines to use. These two have similar (though not equal) volumes, but the Oxygen is heavier in an obvious ...
AlanSE's user avatar
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12 votes
1 answer
3k views

The principle behind regenerative cooling?

In regenerative cooling the fuel is passed around the nozzle before being pumped into the combustion chamber right? I don't really see how this affects cooling itself, since the heat captured around ...
user2277550's user avatar
12 votes
1 answer
3k views

Why is an inflatable balloon inside a fuel tank not used to prevent fuel from "sloshing around"?

After seeing all the Starship failures, having something with a membrane keep things in place seems like an obvious solution. Has it been considered or tested - or do we simply lack a material that is ...
Dagelf's user avatar
  • 517
12 votes
3 answers
739 views

Does ISRO's Cryogenic Upper Stage have restart capability?

Does the CUS of ISRO have restart capability? If so why was it not tested in the recent GSLV-D5 flight? Maybe by restarting the stage after S/C release? What enhancements are required to make a ...
juvva's user avatar
  • 391
12 votes
1 answer
267 views

What cryogenic selective surface materials have high Technology Readiness Level?

NIAC ("NASA Innovative Advanced Concepts") has approved the following research application for 2015 funding: https://www.nasa.gov/feature/cryogenic-selective-surfaces Cryogenic Selective ...
Deer Hunter's user avatar
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11 votes
1 answer
3k views

How did the Space Shuttle keep its cryogenic fuel cold?

As I understand it, the Space Shuttle used cryogenic fuel in its main engines and it kept a supply onboard for the duration of its mission for a deorbit burn. Since Space Shuttle missions often lasted ...
Keavon's user avatar
  • 395
11 votes
1 answer
1k views

Falcon-9's subcooled LOX is continuously refrigerated in-situ, what about its subcooled RP-1?

@Uwe's answer to Why would sub-cooled LOX tanks need to “topped-off” until the last minute or so? explains how subcooled LOX is kept cold and dense by "in situ refrigeration"; helium is bubbled ...
uhoh's user avatar
  • 149k
10 votes
3 answers
1k views

A cryo tank within another cryo tank...is it a sound engineering concept?

Here's the idea: A large spherical LH2 tank is placed inside a spherical LOX tank. The reason I thought of this is so the inner tank doesn't need to be insulated. It doesn't need to be a double-...
DrZ214's user avatar
  • 4,596
10 votes
2 answers
2k views

Why can’t cryogenic propellants be storable, at least on the ground, via refrigeration?

Cryogenic fuels (liquid hydrogen, liquid methane)1 and oxidisers (liquid oxygen)2 are the rocket propellants of choice where raw performance is the overriding concern, due to the very high performance ...
Vikki's user avatar
  • 4,157
9 votes
2 answers
2k views

Why is the hot part of Webb's MIRI cryocooler in the 300K area?

Longer wavelengths require cooler temperatures to detect efficiently. The MIRI detects all the way out to 25 μm and so needs to be cooled to 7 K. Webb can passively cool down to 40 K with its sun-...
Kevin Kostlan's user avatar
9 votes
3 answers
3k views

How was the Centaur stage fueled in the Space Shuttle?

The Space Shuttle had the ability to launch Centaur booster stages stored inside of the Shuttle during launch. How was this stage fueled, being fueled with cryogenic fuels?
PearsonArtPhoto's user avatar
  • 121k
9 votes
4 answers
1k views

How difficult is it to convert a hypergolic based Moon human lander to a cryogenic one?

Recently a study performed by Aerojet Rocketdyne indicated that in order to achieve a 2024 landing using storable propellants will be required. Given that NASA is looking to reduce program risk in any ...
Barry Jenakuns's user avatar
9 votes
2 answers
3k views

Why do Ariane rockets not have ice break off on liftoff?

In a recent question asked here, it was asked what debris falling from a Rocket Lab Electron Rocket was during launch. e.g.: The answer, was that it was ice that had formed after cryogenic fuel/...
Tom J Nowell's user avatar
9 votes
2 answers
902 views

Propellant boil-off in zero G

The Falcon Heavy test flight included a demonstration of capability to coast for several hours and then re-light the second stage for a final burn. During the coast, the cryo propellants are absorbing ...
Anthony X's user avatar
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9 votes
1 answer
210 views

Has solidifying liquid propellant been considered for space exploration?

Liquid hydrogen is $0.071 g/cm^3$ Solid hydrogen is $0.086 g/cm^3$ Since denser fuel is desirable, has solid hydrogen been considered for use in space exploration? I suspect the very low ...
Antzi's user avatar
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9 votes
1 answer
526 views

ULA's ACES upper stage with IVF - Why are they using internal combustion engines?

I recently read out about ULA's ACES (Advanced Cryogenic Evolved Stage) upper stage with IVF (Integrated Vehicle Fluids), which crazy as it sounds, has two six-cylinder engines developed by Roush that ...
masospaghetti's user avatar
8 votes
4 answers
7k views

Autogenous pressurization with sub-cooled propellant

In his IAC 2016 talk, Elon Musk said (at 28m 4s in the video) that the ITS booster tanks would use autogenous pressurization. This means there is gaseous oxygen resp. methane in the tank. To stay ...
oefe's user avatar
  • 2,179
8 votes
1 answer
858 views

How will Robotic Refueling Mission-3's liquid methane tank remain full for six months without any boil off?

Space.com's Lasers, Crystals and 36,000 Worms Will Ride a SpaceX Dragon to Space Station says: To fly on those journeys, astronauts might have to someday harvest fuel from the surface of the moon ...
uhoh's user avatar
  • 149k
7 votes
1 answer
3k views

If a rocket launch is delayed, what happens to the cryogenics?

On February 8, SpaceX had to scrub a launch due to an Air Force technical problem. What happens to the cryogenic fuels when such a launch is delayed? Are the tanks (LOx for the Falcon 9) drained? Are ...
dotancohen's user avatar
  • 6,784
6 votes
2 answers
1k views

What's the difference between cryogenic and Liquid propellant?

According to my understanding (which may be incorrect), the cryogenic form and liquid form of propellant both use a fluid as an oxidizer and fuel. Research tells me crygenic propellant is more ...
Aerospace_Nerd's user avatar
6 votes
1 answer
697 views

How cryogenic oxygen was heated up for CM cabin repressurization?

In related question How was temperature and humidity maintained inside the Apollo mission capsules? the basic concept of conditioning Apollo mission capsules environment is described. After ...
Sergiy Lenzion's user avatar
5 votes
1 answer
350 views

Does a cryogenic liquid propellant engine exist capable of using multiple fuels?

For example, a rocket engine which can use both liquid methane and liquid hydrogen.
peterh's user avatar
  • 3,298
5 votes
1 answer
287 views

What methods are proposed for storing cryogenic fuels (esp. hydrogen) in space for months or years?

Current Launch vehicles and upper stages must only keep their fuels for minutes or hours, so they are only insulated to keep boiloff to a few % per day - I've seen 21% per day quoted for Centaur on ...
Talisker's user avatar
  • 352
5 votes
1 answer
470 views

Insulation used in the plumbing line of the actual rockets

While using the pipes for plumbing of the liquid propellants at pretty low temperature because of which ice form on the line if not insulated or poorly insulated, which can lead to liquid to gas ...
Amar's user avatar
  • 2,246
5 votes
1 answer
167 views

What temperature difference do the injectors in a cryo engine experience?

A quick follow-up to Does ISRO's Cryogenic Upper Stage have restart capability? What temperature difference do the injectors in a cryo engine experience between the propellant tank, and the ...
Everyone's user avatar
  • 13.6k
5 votes
2 answers
133 views

What propellant (coolant) mass is required for an actively cooled heat shield?

Stoke Space are using a regeneratively cooled heat shield to allow their second stage to survive re-entry. The basis of the design flows LH2 through the aeroplug, then using the heat captured to power ...
Barry Jenakuns's user avatar
4 votes
2 answers
345 views

How does the open expander cycle separate the fuel for the pump and combustion chamber? [closed]

I'm designing a single open cycle expander rocket engine using propane. However, I've been unable to find out whether or not the fuel is split into the turbine and combustion chamber before or after ...
R. Hall's user avatar
  • 822
4 votes
1 answer
217 views

Air-launching an Electron-like LOX-based rocket from a plane; technical challenges?

@GremlinWranger's answer and comments to the question Is it coincidence that the Electron has very similar dimensions to the Pegasus? motivates my asking for the technical challenges to air-launching ...
uhoh's user avatar
  • 149k
4 votes
1 answer
620 views

Liquid Helium (4.2K) sealed, then raised to sub-LOX temperature (~70K) - what is the new pressure?

In this question there is discussion of the large differences in temperature between liquid helium-4, subcooled liquid oxygen (sub-LOX) and cold kerosene (RP-1). Approximate temperatures are 4.2K, ~...
uhoh's user avatar
  • 149k
4 votes
1 answer
598 views

Why are propellant tanks filled from the bottom?

It seems that the norm is to (fast-) fill fuel and oxidiser tanks from the bottom. For example, on this drawing of the Saturn S-IC stage you can see the LOX and RP-1 fill valves at the bottom of the ...
Ludo's user avatar
  • 14.4k
4 votes
1 answer
197 views

Could IR space telescopes and other very cold devices use Zeeman slowers effectively in the near term?

Infrared telescopes need to be very cold (often below 10 K) to be effective. So do a few other miscellaneous things, including superconductors, if we ever use them in space for e.g. mass drivers or ...
Nathan Tuggy's user avatar
  • 4,567
4 votes
2 answers
369 views

Are cryo tanks heavier than normal tanks (on a per surface area basis)?

From my related question, it turns out cryo tanks are not double-walled for insulation purposes. So now I will continue along a similar line and ask, aren't cryo tanks heavier than normal tanks on a ...
DrZ214's user avatar
  • 4,596
4 votes
0 answers
246 views

Is ISRO Making a Methane Engine?

I'd read some stray comment on the internet claiming that ISRO is working on a methane-LOX engine, just as a technology demonstrator. Is this true?
san man's user avatar
  • 41
3 votes
1 answer
218 views

In a rocket engine, do the propellants come out as liquid or gas if they’re cryogenic?

My cousin and I were talking about this and we could not come to a conclusion. Obviously it is very hard to keep cryogenic propellants at a liquid with the temperatures involved, but if they ...
MrChemistryCow's user avatar
3 votes
2 answers
406 views

Cryogenic storage in Starship header tanks

Since Starship uses cold liquid oxygen and methane fuel in its header tanks, how will these cryogenic tanks been kept full and cold on long missions in space?
Starski's user avatar
  • 51
3 votes
1 answer
163 views

Cryogenic systems in kwajalein Island- Spacex- falcon 1

Is the LOX (liquid oxygen) required for the falcon-1 launch transported or produced? If transported, how? If produced, did they set up a cryogenic oxygen plant in Kwajalein?
Vasanth C's user avatar
  • 1,161
3 votes
1 answer
235 views

How would cryogenics work to keep a pilot alive during long term travel?

How would a cryofreeze work in order to keep the pilot alive long enough to survive an automated travel to some destination?
Vnge's user avatar
  • 297
3 votes
1 answer
880 views

How do Expander Cycle Engines Inject Liquid Fuel During Startup?

My understanding is that the H2 in an expander-cycle engine is vaporized by the heat from the combustion chamber and nozzle wall. This is used to power a turbine and then get injected, in gas phase, ...
Orion DeYoe's user avatar