55 votes
Accepted

Using ozone as oxidizer

The book 'Ignition!' tells the history of propellant research and has this to say about ozone from page 112 available here For it has its drawbacks. The least of these is that it's at least as ...
OrangePeel52's user avatar
  • 2,561
28 votes

Why do $\text{CH}_4$ (Raptor) engines produce less soot than RP-1 (Merlin) engines?

As GandalfDDI notes, you always run your engine fuel-rich so it doesn't start running engine-rich. This results in incomplete combustion of the fuel. Methane is a single carbon atom bonded to four ...
Mark's user avatar
  • 14.1k
25 votes
Accepted

Why does the 2nd stage of Falcon 9 need compressed He tanks?

The helium is used to continuously re-pressurise the propellant and LOx tanks as they are emptied. It is stored in a COPV inside the body of the LOx tanks to keep the He at a lower temperature (and ...
Jack's user avatar
  • 9,976
25 votes

Why do $\text{CH}_4$ (Raptor) engines produce less soot than RP-1 (Merlin) engines?

As explained to me (carefully and fully) by a Rocketdyne engineer you ALWAYS run rocket engines fuel rich. If you run lean the oxidizer looks at the metal parts of the engine (remember the engines are ...
GandalfDDI's user avatar
22 votes

Using ozone as oxidizer

Ozone is not stable, storing in liquid form as a solution in LOX requires stabilizers. It will oxidise most metals. A gaseous mixture of ozone and oxygen may decompose explosively. And it is poisonous ...
Uwe's user avatar
  • 1,714
16 votes
Accepted

Other than He and N as pressurizing gases

A good pressurizing gas needs to satisfy a few basic properties: it needs to stay gaseous at the temperatures and pressures your fuel and oxidizer are stored at, so that it won't just condense out ...
Ilmari Karonen's user avatar
13 votes
Accepted

There are better oxidizer than oxygen?

This depends on what "better" is. But let us talk about fluorine. The main point of using it is that turning your hydrogen into $HF$ gives more energy than getting $H_2O$ for pure hydrogen, that ...
SE - stop firing the good guys's user avatar
12 votes

HTP as oxidizer for main propulsion

HTP has been used as an oxidizer before. Kind of. See BLACK ARROW and the rest of the British keroxide. Turns out HTP by itself isn't a great oxidizer, but when you catalyze its decomposition into ...
Anton Hengst's user avatar
  • 10.6k
12 votes

Can the higher oxides of nitrogen, like nitrogen pentoxide, be used as oxidisers in rocket engines?

Not likely N2O5 Well, the stuff IS a very strong oxidizer. But considering that the solid form is a hard white salt-like substance, and it melts at 41 °C, and boils at 47 °C, so it can be a wee bit ...
CuteKItty_pleaseStopBArking's user avatar
10 votes
Accepted

Could H₂S₂O₈ (peroxydisulfuric acid), made in the clouds of Venus, be used for making a propellant?

The problem in making propellant on Venus, is surely in finding the fuel, rather than the oxidizer. Oxygen can be made by electrolyzing $\text{CO}_2$ if necessary and while $\text{S}_2\text{O}_8^{2-}$ ...
Steve Linton's user avatar
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9 votes
Accepted

What are the advantages of Ox-rich staged combustion?

According to the super-detailed and very informative NASA-CR 165404 Fuel/Oxidizer-Rich High-Pressure Preburners, the primary advantages of hydrocarbon-fueled oxidizer-rich staged-combustion engines is ...
Organic Marble's user avatar
9 votes
Accepted

Why does Juno use "mixed oxides of nitrogen" oxidizer for propulsion? Which ones?

MON according to Wikipedia: Mixed oxides of nitrogen (MON) are solutions of nitric oxide (NO) in dinitrogen tetroxide/nitrogen dioxide (N2O4 and NO2). The addition of a small amount of nitric ...
Russell Borogove's user avatar
8 votes

Why aren't airbreathing SRBs a thing?

You'd need a complex intake: it has to be closed during ignition, with a large closing force (otherwise you'd have half the thrust going out the intake), then it has to move out and keep changing its ...
Hobbes's user avatar
  • 124k
7 votes

Could H₂S₂O₈ (peroxydisulfuric acid), made in the clouds of Venus, be used for making a propellant?

Peroxydisulfates and peroxydisulfuric acid itself would be a bad choice for rocket oxidizers for several reasons: H2S2O8 is actually a solid with melting point of 65°C, therefore unsuitable for ...
WOW 6EQUJ5's user avatar
  • 2,223
7 votes

There are better oxidizer than oxygen?

Besides pure oxygen, several other oxidizers in theory have better performance with hydrocarbon fuels, but none of them are used because of stability, toxicity and price issues. But let mention some ...
WOW 6EQUJ5's user avatar
  • 2,223
7 votes
Accepted

Is a fluorine/hydrogen engine feasible for use in space?

The safety-related costs of developing, testing, and fueling fluorine-oxidized rockets outweigh the costs of building slightly bigger and less efficient rockets using hypergolics or LOX. In launcher ...
Russell Borogove's user avatar
7 votes

What are the energy-to-mass ratios of some fuels/oxidizers, when including the oxidizer?

First we have to go back to the chemical equations, and this time, include the standard enthalpy of combustion. Hydrogen: 2 H$_2$ + O$_2$ → 2 H$_2$O + 572 kJ/mol Methane: CH$_4$ + 2 O$_2$ → CO$_2$ + ...
DrZ214's user avatar
  • 4,566
7 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 ...
GremlinWranger's user avatar
6 votes
Accepted

Could you use Helium as an oxidizer?

Helium is a noble gas, meaning it does not react with other atoms. In fact, it is the least reactive of them all. No compounds containing helium has ever been found, although some of the heavier noble ...
SE - stop firing the good guys's user avatar
6 votes

Why can I not use stoichiometry to calculate the O/F ratio of my rocket?

Rockets frequently (potentially even usually) are not operated stoichiometrically, as this tends not to be the most efficient operating point. The most extreme example is that of the H2/O2 rocket, ...
ikrase's user avatar
  • 8,587
6 votes
Accepted

What is the products of a catalyzed reaction between Hydrogen Peroxide and Ethanolamine with Copper(II) Chloride?

TL;DR: The result will probably be mostly water with significant proportions of carbon dioxide and nitrogen gas. Small proportions of copper(II) oxide and hydrochloric acid may also be released. There ...
WaterMolecule's user avatar
5 votes
Accepted

Propellant filling rate in propellant tanks

I probably shouldn't answer this question, then again I can't vote to close because it is to broad and ambiguous, so I will try and give an suitable answer to help the OP out. First aspect: What is ...
anon's user avatar
  • 1,010
5 votes

Can LOX containing hydrogen peroxide be used as an oxidizer for a liquid fueled rocket?

Sources here and here, see also Supply of liquid oxygen (LOX) maintained on the ISS? Kept cold using “space”, or refrigerator? A quick check via google for "liquid oxygen with hydrogen peroxide" ...
uhoh's user avatar
  • 149k
5 votes

Why does Juno use "mixed oxides of nitrogen" oxidizer for propulsion? Which ones?

The use of MON, as distinct from N2O4, arose because the latter can cause stress corrosion cracking (SCC) of titanium alloys. This was first observed in the 1960's during the development of the Apollo ...
Barrie Mellor's user avatar
5 votes

How long can a vehicle stay fueled before the liquid oxygen gets too warm?

They're subcooling the LOX in order to get more oxygen in the tank. The lower temperature translates to something like 3% more oxygen (by weight) in the same volume. When the LOX warms up, it expands ...
Hobbes's user avatar
  • 124k
5 votes
Accepted

How long can a vehicle stay fueled before the liquid oxygen gets too warm?

Normal vehicles that use LOX, use it at the normal temp (-183C) and what they do is let the LOX boil off, and refill it right up to the latest possible moment their hardware allows. The Falcon 9 1.1 ...
geoffc's user avatar
  • 79.1k
4 votes

Specific Energy counterpart for oxidizers

A good way to get a feel for the relative strengths of various oxidizers is to compare their standard reduction potentials. Fluorine is one of the most potent oxidizers known, with a reduction ...
Qubit1028's user avatar
  • 216
4 votes

Is there any practical application of trinitramide N(NO2)3 in rocket propellants

Note that the original research from the 90s determined that it should be "stable"--but stable is not a binary state! It's stable enough that they can make it in the lab under carefully ...
Loren Pechtel's user avatar

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