All Questions
21
questions
11
votes
2
answers
4k
views
Why are nitric acid and hydrogen combinations not used as rocket fuel?
I was recently doing a chemistry assignment about bond energy when I noticed the incredibly low bond energy of nitric acid. Given the high bond energy of a nitrogen triple-bond, this set me wondering ...
6
votes
1
answer
85
views
Important new additives to hypergolic hydrazine-based fuels since 1972?
In "Ignition! An Informal History of Liquid Rocket Propellants", John D. Clark in one of the chapters gives an overview of the then current state of hydrazine and hydrazine derivatives.
The ...
10
votes
3
answers
3k
views
Why do $\text{CH}_4$ (Raptor) engines produce less soot than RP-1 (Merlin) engines?
SpaceX's Merlin engine, which burns RP-1 and LOX, has soot visible after the first stage lands. Many articles on the web say SpaceX's Raptor engine, which burns methane and LOX, is clean. ...
- 2,888
6
votes
1
answer
480
views
Can the higher oxides of nitrogen, like nitrogen pentoxide, be used as oxidisers in rocket engines?
Both nitrous oxide (N2O) and dinitrogen tetroxide (N2O4) are used in storable propellant combinations, so, simply as a continuation, can the higher oxides of nitrogen (N2O5, N2O6, etc.) still be used ...
- 822
8
votes
1
answer
638
views
Silane as a rocket fuel
At about 6:55 into the video Why Moon Mining Will DEFINITELY Be A Thing it is stated that lunar silica (SiO2) could be turned into silane (SiH4), which is the silicon analogue of methane. It also ...
- 13.1k
3
votes
2
answers
259
views
Can pyroxene and other silicon compounds be used as a theoretical spacecraft fuel?
I have been reading this patent, which led me to this paper.
The first uses polysilane, which basically replaces the $\text{C}$ in a $\text{-R-C-R-}$ group, making an $\text{-R-Si-R-}$ group. I also ...
- 213
4
votes
1
answer
1k
views
If high-test peroxide is most stable when pure, why are most uses of it in rocketry at lower concentrations?
Per the Wikipedia article for High-test peroxide:
Hydrogen peroxide becomes more stable with higher peroxide content. For example, 98% hydrogen peroxide is more stable than 70% hydrogen peroxide. ...
- 461
3
votes
1
answer
314
views
Dinitrogen tetroxide decomposes to nitrogen dioxide at room temperature, but rockets that use it are usually said to use N₂O₄ and not NO₂ - why?
To the best of my understanding, both dinitrogen tetroxide and nitrogen dioxide are usable and perform quite similarly as oxidizers, but rockets that use either are almost always said to use ...
- 461
4
votes
0
answers
262
views
Why didn't propylene fly? (Vector—yes, Vector—is back)?
Ars Technicha's Rocket Report: SLS has technical problems, Vector—yes, Vector—is back links to Vector restarting operations under new ownership which says:
One thing they did wrong was the technology ...
- 148k
1
vote
0
answers
436
views
Can Chemical Engineer work on something related to space?
I am an undergraduate student (scientific section) living in Qatar. I have a big interest in astronomy and astrophysics and have participated in the IOAA (International Olympiad on Astronomy and ...
- 11
4
votes
3
answers
452
views
Options for making rocket fuel using the Moon's natural resources
Based on what is known about the chemistry of the lunar surface through remote sensing and surface exploration, what raw ingredients are likely to be available that can be used to make rocket fuel?
- 41
2
votes
1
answer
149
views
Molecular propellant in ion engines
This question was prompted by discussions on this question. Can there be an advantage to using a molecular propellant in an ion engine, as opposed to noble gasses or iodine? (Although iodine actually ...
- 4,287
8
votes
2
answers
4k
views
What are the energy-to-mass ratios of some fuels/oxidizers, when including the oxidizer?
Energy-to-weight ratio is an important parameter. We would like it to be high so we don't have to carry around much fuel.
Maybe you've heard some of the numbers for common fuels. Hydrogen is about ...
- 4,596
6
votes
1
answer
12k
views
Can I make my own RP1? [closed]
Is it possible for me to buy kerosene from a local store and then try to refine it to the extent where it would be considered RP1. If so how would I do it? For those who are wondering me and a group ...
- 167
2
votes
1
answer
154
views
What is $C_p$ in the fuel efficiency equation?
On page 94 of Ignition! an equation for "Frozen equilibrium calculation":
$$
c = \left[ 2H/M \right]^{1/2} \left[ 1- \left( {P_e \over P_c} \right) ^{R/C_p} \right]^{1/2}
$$
All quantities are ...
- 55.1k