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.
67
questions
5
votes
2
answers
153
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 ...
- 7,403
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 ...
- 170k
3
votes
0
answers
201
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://...
- 22.9k
3
votes
1
answer
198
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 ...
- 5,884
2
votes
2
answers
194
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 ...
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 ...
- 466
0
votes
1
answer
97
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) ...
- 184k
33
votes
1
answer
29k
views
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 ...
4
votes
2
answers
351
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 ...
- 13.1k
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 ...
- 1,544
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-...
- 1,696
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-...
- 601
3
votes
1
answer
899
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, ...
- 184k
19
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 ...
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 ...
- 149k