40
votes
Why can't cryogenic oxygen and cryogenic kerosene be "stored" together?
As Organic Marble hints, there is about 140 degrees Celsius between kerosene's freezing point and oxygen's boiling point; there's no temperature at which both are liquid.
Even if the propellants were ...
- 165k
36
votes
Accepted
Why would sub-cooled LOX tanks need to "topped-off" until the last minute or so?
At a pressure of 1 bar, the temperature of liquid boiling oxygen stabilizes at 90 K. For sub-cooling of LOX, the temperature should be lower. It is possible to cool LOX by forced evaporation by a ...
- 48.4k
31
votes
Accepted
What is "anti-geysering" and why would you turn it off 70 seconds before launch?
Partial answer to
What is "anti-geysering"...
tl;dr Anti-geysering systems are intended to stop geysering, which is a phenomenon that can occur in long vertical pipes of cryogenic fluid ...
- 174k
22
votes
Why can't cryogenic oxygen and cryogenic kerosene be "stored" together?
Because it will almost certainly go KABOOM.
Intimately mixed fuels and oxidizers are pretty much indistinguishable from explosives, and in particular, LOX intimately mixed with flammable hydrocarbons ...
- 8,588
21
votes
Accepted
How do rockets keep their fuel in a liquid state?
As small amounts of LOX boil off heat is removed from the remaining volume. Boiloff actively cools the fluid and helps keep the remainder liquid. Rockets typically have vents to aid in managing the ...
- 6,417
21
votes
Why a 900,000 gallons LOX storage tank at Launch Complex 39?
Excess capacity was needed in the storage sphere to allow for multiple attempts in a launch campaign.
Much of the propellant was recovered during a scrub but not all.
The storage spheres were loaded ...
- 174k
18
votes
Falcon-9's subcooled LOX is continuously refrigerated in-situ, what about its subcooled RP-1?
RP-1 isn't cryogenic actually. The subcooling for RP-1 is only to cool it to slightly below the freezing point of water, 20 F. At that temperature, no extreme cooling is required. The temperature ...
- 121k
15
votes
A cryo tank within another cryo tank...is it a sound engineering concept?
...is the tank within a tank a sound engineering concept for rocket
stages?
I take this to mean that you are not talking about pressurant bottles or other small devices submerged in the propellant ...
- 174k
15
votes
Why isn't LOX/UDMH used in staged combustion rockets now-a-days?
N2O4/UDMH is the choice if you need a non cryogenic storable hypergolic fuel. But UDMH is toxic and carcinogenic and should be avoided if possible. UDMH is also corrosive. LOX/UDMH is not storable (...
- 48.4k
14
votes
Accepted
Is this explanation for the SpaceX 1-Sept-2016 anomaly plausible?
Edit Jan 2, 2017: Well, it was a COPV bottle after all. There were buckles in some liners where super-cooled liquid oxygen pooled. From NASAspaceflight article, quoting the results of the ...
- 21.2k
13
votes
Accepted
Liquid fuel / Oxygen proportions
There is indeed a ratio of fuel to oxidizer that yields complete combustion, called the stoichiometric ratio. This produces the most thermal energy from combustion, but for a few different reasons, ...
- 165k
13
votes
Accepted
Concerns/challenges with LOX as a regenerative coolant
To answer your first question: one of the main problems with using the oxidizer in general is oxidizing of the cooling channels. Any hot oxidizer has this problem, but oxygen definitively has this ...
- 1,054
12
votes
How (actually) do sub-cooled propellants reduce cavitation within turbo pumps and make feed easier?
Cavitation is boiling, in this case it is caused by reduced pressure in the wake of blades. A boiling point is a combination of 2 factors; heat and pressure. If you can't do anything about the reduced ...
- 4,824
11
votes
How much liquid oxygen is lost during a Space-X Crew Dragon launch abort?
Calculating how much LOX is lost is going to be an interesting calculation, but I'm not sure we have the data for that. Instead, I'll be focussing on the other part of your question:
Is the loss ...
- 601
11
votes
Accepted
F1 engine turbopump
Short answer:
shock loads due to high acceleration of the turbopump shaft
rubbing between critical seals and other moving parts
fatigue in the impeller section
Directly quoting from this link:
The ...
- 130
10
votes
Accepted
How do they know how much liquid propellant is in a rocket just before launch?
The shuttle external tanks used liquid level sensors. You can see them on the left side of each tank in this schematic.
Source: Page 95 of the old Press Manual
Related sensors gained notoriety late ...
- 174k
10
votes
F1 engine turbopump
The four destructive LOX pump failures had happened at 110, 110.5, 107.7 and 109 sec; this looked statistically significant, but after much study the team wrote it off to a freak coincidence. ...
- 174k
8
votes
Accepted
Why doesn't carbon fiber overwrapping in LOX catch fire? (watch this video first)
Liquid oxygen mixed with carbon powder has been used as an explosive for mining, see 1, 2. But there has been an explosion in a helium purifier 3.
The use for mining required safe explosives, the rate ...
- 48.4k
8
votes
How did JPL detonate a liquid oxygen methane mixture with light?
At low temperatures, the activation energy for pure CH4 O2 oxidization is about 170kj/mole. (See figure 1 here) That’s about 1.8eV per atomic reaction.
1.8eV can be provided by 688nm red light, or ...
- 12.5k
7
votes
Accepted
Comparison of rocket engines using LH2 & LOX as propellants
There was a large difference in their size, and at the time, they were developed by two entirely different companies.
In general, the propellant combination of a rocket engine does not determine its ...
- 165k
6
votes
Accepted
Supply of liquid oxygen (LOX) maintained on the ISS? Kept cold using "space", or refrigerator?
Hard to prove a negative, but no, there is no provision for storing LOX on the ISS. The coldest thing up there is the MELFI, the Minus Eighty Degree Laboratory Freezer (for) ISS.
Oxygen (and ...
- 174k
6
votes
How can the elements involved in loading a LOX tank be involved in an explosion?
Just to mention one facet of this multifaceted problem,
any electrical field potential that exists (i.e. items that aren't on a common bias electrically) can and usually will at some point create an ...
- 119
6
votes
Why isn't LOX/UDMH used in staged combustion rockets now-a-days?
The reason you go with UDMH/NTO F/O pair is storability, i.e. the ability of your rocket or missile to be stored, fully fueled straight from the factory, in a silo or stand on a launch rack for an ...
- 1,326
6
votes
Why a 900,000 gallons LOX storage tank at Launch Complex 39?
Partial answer: I can identify the manager responsible for the decision, and the date, but not the reason why.
LC-39 was the sole topic at a meeting of the Launch Operations Working Group on 18-19 ...
- 47.4k
6
votes
Was liquid ozone + fluorine ever tested as an oxidizer? Ever with jet fuel?
A not up to date answer but in 1972 J Clark in Ignition writes that cryogenic Oxygen+Ozone was investigated and found to be relatively stable* before use but having some exciting properties for any ...
- 20.7k
5
votes
Accepted
Filling of LOX tanks - 'cryogenic geyser cycling'
A cryogenic geyser occurs when a volume of cryogenic liquid inside e.g. a pipe suddenly boils, propelling the liquid/gas mixture through the pipe and into its destination at high speed.
The pipe ...
- 123k
5
votes
How (actually) do sub-cooled propellants reduce cavitation within turbo pumps and make feed easier?
This answer is based mostly on the NPSH link Organic Marble shared (http://www.pumpschool.com/applications/NPSH.pdf) and the various properties you can infer about subcooled LOX.
Subcooling lowers ...
- 9,245
5
votes
Accepted
Is the Paramagnetism of Liquid Oxygen Ever Considered in Engine or Tank Design?
Check out this article and the sources cited: Simulation of LOX reorientation using magnetic positive positioning https://link.springer.com/article/10.1007/BF02908417
Looks like it has been studied.
...
- 66
5
votes
Is the Paramagnetism of Liquid Oxygen Ever Considered in Engine or Tank Design?
LOX is paramagnetic, not fully magnetic. What does that mean? It takes an extremely large magnet to have any effect at all. The only design consideration which would need to occur at all would be to ...
- 121k
5
votes
Accepted
What is the blue/red flare at the Delta IV Heavy launchpad
The answers on the reddit thread you linked are essentially correct. The camera angle is the only difference between the two images, making the flare appear further away.
As you mention, Delta IV and ...
- 9,944
Only top scored, non community-wiki answers of a minimum length are eligible