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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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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
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
3 votes
0 answers
189 views

Does Starship run on Slushies?

Cryogenic slush (a mixture of liquid and solid) can potentially store propellants at higher density than cryogenic liquid. For instance, hydrogen slush is 16-20% denser than liquid hydrogen. https://...
Woody's user avatar
  • 22.4k
2 votes
2 answers
189 views

Can surrounding methalox by hydrolox save it from boil off

In case of a (single) Starship (as a) fuel depot orbiting the Earth, how can we prevent boil off, may be so? Some fuels have lower temperatures such as hydrolox is colder than methalox. Could we may ...
estinamir's user avatar
  • 401
3 votes
1 answer
193 views

Prevent boil off in StarShip fuel depot by a JWST-like sunshield?

Can we use Webb’s telescope shield to prevent or significantly reduce boil off of propellant from StarsShip fuel depot, made from a single StarShip in Earth orbit? For JWST, its sunshield covers its ...
estinamir's user avatar
  • 401
0 votes
1 answer
95 views

Semi-Cryogenic HTP/LH2 engine?

Also see HTP as oxidizer for main propulsion (for more info on history of H2O2/HTP in rocketry) Note: HTP and H2O2 will be used interchangeably I know the Black Arrow LV (The first orbital lipstick) ...
AnarchoEngineer's user avatar
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
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
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
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
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3 votes
2 answers
407 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
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4 votes
2 answers
347 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
9 votes
1 answer
527 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
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
2 votes
1 answer
408 views

How is Cryogenic fuel kept... Cryogenic in rockets [duplicate]

How is cryogenic fuel & oxidizer kept at cryogenic temperatures in rockets? I am mostly interested in the first stage of launch vehicles rather than something like a Centaur that keeps hydrolox ...
YuccaWorks's user avatar
3 votes
0 answers
240 views

What is the record for LOX staying liquid in space?

Liquid oxygen can be used for breathing, for fuel cells, and as an oxidizer for propulsion. However, it is cryogenic, and will slowly boil off in storage, even in a spacecraft. What is the longest ...
DrSheldon's user avatar
  • 48k
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
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
3 votes
1 answer
220 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
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
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
3 votes
1 answer
884 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
1 vote
0 answers
34 views

Can anyone suggest me some resources for studying about the different types of cryogenic valves and their design aspects [closed]

Book titles, videos, articles or any other resource that I could refer
SANGEETH A K's user avatar
1 vote
1 answer
227 views

Could in situ (in-rocket) evaporative cooling/refrigeration be used for methane or hydrogen cryogenic propellants?

@Uwe's excellent answer to the question Why would sub-cooled LOX tanks need to “topped-off” until the last minute or so? explains that the LOX is sub-cooled in situ within the rocket's tank using ...
uhoh's user avatar
  • 149k
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
0 votes
0 answers
205 views

How would a body be stored in a dark hole in the moon?

How well would the human body stay preserved if it was frozen while pressurized and vacuum sealed before being placed in a crater on the Moon? Would the temperature be more reliably stable on the moon ...
Muze's user avatar
  • 1
2 votes
0 answers
92 views

LOX as annular heat sink

I'm thinking of my time spent working with cryostats. Liquid helium pot on the inside, and surrounded by a liquid nitrogen jacket. And the whole thing insulated with vacuum and superinsulation. (...
Greg's user avatar
  • 4,287
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
1 vote
0 answers
159 views

Cryogenic liquid pressurization resulting in overpressurized tank

I want to pressurize a cryogenic liquid (LN2 in this test. Eventually LOX). I have a setup similar to this and follow a similar procedure to what is described, but I don’t see the same tank pressure ...
Vistalop's user avatar
8 votes
1 answer
859 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
2 votes
2 answers
456 views

Why are LOx plumbing not insulated?(ref: Huzel and Huang)

In the book Modern Engineering for Design of Liquid Propellant Rocket Engines, the following excerpt appear in chapter 9 - Interconnecting Components and Mounts: The liquid-oxygen lines were not ...
karthikeyan's user avatar
  • 4,479
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
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
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
  • 55.1k
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
  • 4,479
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
2 votes
1 answer
408 views

Filling the propellants in the rocket tanks

After putting the rocket on the launch pad the propellants are filled. But before that how to maintain the lower temperatures of the tanks so that when filling the propellants don't boil off?
Amar's user avatar
  • 2,246
1 vote
0 answers
62 views

Cryogenic engines till date

How many cryogenic engines are there till date. Names are mostly necessary.
Amar's user avatar
  • 2,246
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
3 votes
1 answer
413 views

Falcon-centaur or Falcon-ACES?

For very high delta-V missions (eg outer solar system) the Falcon family really starts to suffer from that fact that its second stage is still using RP-1/LO2 rather than LH2/LO2 with a consequently ...
Steve Linton's user avatar
  • 19.6k
2 votes
1 answer
1k views

ULA's plan for LH2/LOX 2nd stage that can maintain propellant for an extended period of time?

Business Insider's (long) article SpaceX's biggest rival has a 'genius' plan to cut its rocket launch costs more than 70% contains the statements sourced from ULA's CEO Tory Bruno: Vulcan should ...
uhoh's user avatar
  • 149k
9 votes
2 answers
903 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
  • 17.6k
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
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
4 votes
1 answer
621 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
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
  • 12.7k
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
0 votes
1 answer
746 views

Is the "cryogenic helium" system in recent discussions actually LHe for cryopumping?

I am wondering if the "cryogenic helium" system discussed in articles about the 1-Sept-2016 SpaceX Falcon 9 anomaly (see this answer for a good summary to date) is not actually related to the high ...
uhoh's user avatar
  • 149k
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
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
  • 149k