Questions tagged [chemistry]
Questions regarding the application of chemistry in space exploration, for example the composition of rocket propellants.
101
questions
3
votes
1
answer
119
views
What is the maximum possible delta v we could achieve from assembling a chemical rocket in orbit (not launching a final stage from the ground)?
To clarify, this is about an orbital assembly. I am not asking the maximum weight of launch vehicles or anything relating to that.
This is a pure hypothetical scenario in which we have an infinite ...
- 39
4
votes
1
answer
139
views
What is the dark brown gas emission seen during the ascent of Starship?
During the video (see below) of Starship IFT-4 there is a lot of brown smoke or gas in the Superheavy exhaust from near the start for almost 30 seconds. Is this NO2? If so roughly how much is produced?...
- 10.1k
1
vote
0
answers
84
views
What is the ratio of air and ethyl alcohol that must be in order to power a rocket engine? [closed]
There is a rocket engine that will run on a fuel pair: air + ethyl alcohol, but what percentage of components should be supplied ...
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 ...
3
votes
2
answers
181
views
What is the prevalence of nitrogen, phosphorus, and potassium in the asteroid belt and in comets?
As someone with a light background in controlled-environment agriculture, I'm familiar with the importance and use of N/P/K in growing useful plants. This got me thinking about how common these ...
- 516
1
vote
0
answers
144
views
Interpretation of mars rover images
I’ve been obsessed with the perseverance images, specially the images from the SHERLOC-WATSON system- the UV camera tricked out with racing stripes and fuzzy dice hanging from its rear-view mirror (...
- 11
3
votes
1
answer
238
views
Are there any gaseous monopropellants?
There are numerous liquid monopropellants: Hydrazine, Hydrogen Peroxide, Nitrous Oxide, Isopropyl Nitrate, and more.
There are of course also solid monopropellants. (Edit: composite propellants not ...
- 4,596
1
vote
2
answers
101
views
Chemical Problems When Encountering Thin Atmospheric Worlds
Bodies such as Enceladus, Mercury, and Triton, etc... have thin (and often temporary) atmospheres.
When probes or landers encounter the chemicals in such atmospheres in low orbits/landings, they may ...
- 1,179
6
votes
2
answers
261
views
If a spacecraft's double hull filled with water is hit by a micrometeorite, could the water freezing or surface tension stop the leak?
I'm thinking about the possibilities of water storage also serving radiation shielding for long space journeys (months to years).
Assume within the solar system but outside of upper earth orbit. ...
- 263
0
votes
1
answer
189
views
NTR performance of hydrazine compared to ammonia?
Methane, ammonia and water are sometimes suggested as alternatives to hydrogen for a nuclear thermal rocket.
While they have a lower specific impulse, they offer much better density, thrust, and ...
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 ...
3
votes
0
answers
229
views
What is the cause of soot in the plume of the Raptor engine?
Though the Raptor engine burns quite clean, it was clear from some early test flights that it did produce some visible soot:
There have been differing explanations for the exact cause of/source of ...
- 1,140
3
votes
1
answer
372
views
What am I missing about rocket nozzle isentropic flow?
Playing a bit with Cpropep-Web, something looked wrong to me about how it models isentropic flow through a CD nozzle.
I'm taking the RS-25 characteristics as an example. I ask for a frozen equilibrium ...
3
votes
2
answers
140
views
How much solar radiation hits a spacecraft in transit to Mars?
How can I solve for the amount of radiation that hits a Mars transit vehicle, in transit? What formulas should I use? I am mostly focused on solar radiation.
- 31
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. ...
- 2,942
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 ...
- 832
2
votes
1
answer
179
views
Perseverance's First Borehole looks like its particles of sand stuck together by something; composition of this material and source of adhesion?
Resampled and sharpened detail from PIA24796: WATSON Image of Perseverance's First Borehole
This is reminiscent of a day at the beach digging a hole in wet sand. The walls remain standing as long as ...
- 149k
8
votes
1
answer
676
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
9
votes
1
answer
334
views
How do they know that the Dragonfly helicopter won't get quickly coated in tholin muck? Any desliming technology for camera lenses or propellors?
From Air and Space's Dragonfly Is the First Aircraft Built for the Outer Solar System; NASA returns to Saturn’s largest moon with a rover that can fly. which I just found in this heavily-sourced ...
- 149k
18
votes
2
answers
3k
views
How did the kerosene-burning Black Arrow have transparent exhaust? (seems to just "hover" in photos)
Kerosene + LOX rockets have big, bright exhaust plumes, at least in the atmosphere; second stages are are a different matter: Why is the flame of the Falcon 9's 2nd stage (nearly) invisible?
But ...
- 149k
4
votes
1
answer
311
views
Has a spacecraft ever actually sprayed a chemical (or anything) on to another spacecraft intentionally for any reason at all?
The question How many of these six military "orbital threat" techniques have been demonstrated in a (more or less) publicly recognized way? begins:
If you are having a good day then under ...
- 149k
9
votes
1
answer
202
views
Is MOXIE's oxygen ready to breathe or is there CO2 and/or CO that would need to be scrubbed?
MOXIE splits two molecules of martian carbon dioxide into two molecules of carbon monoxide and one molecule of oxygen. Breathing elevated levels of CO2 ranges from unpleasant (to say the least and ...
- 149k
3
votes
2
answers
262
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
3
votes
1
answer
221
views
How did MOXIE "know" that it produced 5.4 grams of oxygen? Did it measure pressure rise in a container or just vent it? Did it use an oxygen sensor?
CNN's Perseverance rover just made oxygen on Mars is great and welcome news! While Ingenuity has been achieving one "first" on Mars Perseverance was quietly achieving yet another.
After ...
- 149k
11
votes
1
answer
334
views
How much is known about those liquid metal droplets orbiting the Earth? (e.g. sizes, composition, orbits...) Are any actually tracked?
The question Orbit Guardians - bs, right? mentions a company proposing a smallsat that will capture then give a roughly 200 m/s retrograde "kick" to liquid metal NaK alloy droplets in LEO ...
- 149k
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
4
votes
1
answer
254
views
What is the products of a catalyzed reaction between Hydrogen Peroxide and Ethanolamine with Copper(II) Chloride?
I found this article about Hypergols, specifically H2O2. It mentions in table 3 and in the body of the paper that they found that Ethanolamine with Copper Chloride reacted vigorously. In my search for ...
- 51
4
votes
1
answer
190
views
What instruments and techniques measured Mars' atmospheric D/H ratio which suggests (all of) it's water didn't evaporate after all?
The Time article Mars Has Much More Water Than Previously Known—But There's a Catch says:
The greater weight of deuterium causes it to behave differently in the Martian atmosphere. While free ...
- 149k
3
votes
1
answer
316
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
265
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 ...
- 149k
11
votes
1
answer
4k
views
How hard is the hardest ice in the solar system? Is it in Pluto's ice mountains?
NPR's Pluto Has White-Capped Mountains, But Not Because There's Snow includes the following:
"Initially, it seemed logical that this high-altitude frost could form like on the Earth," says ...
- 149k
2
votes
1
answer
179
views
Why maintain nominal engine inlet mixture ratio for a gas generator engine?
I was reading up on gas generator cycles and came across the following paragraph talking about fuel or oxidizer rich gas generators and the different mixture ratios for the main combustion chamber ...
- 1,144
2
votes
1
answer
102
views
Specific Heat Ratio for a perfect gas mixture
I am reading Rocket Propulsion Elements by George P. Sutton & Oscar Biblarz, 9th Edition. In the fifth chapter, I was introduce to the specific heat ratio k for the perfect gas mixture, Eq. 5-7:
(...
- 23
12
votes
3
answers
921
views
Phosphine, yes -- but where are the organic compounds on Venus?
There has been much speculation in recent news about the finding of phosphine on Venus, and what may be producing it.
At the same time, when we look for clues of life elsewhere in the Solar System, we ...
- 8,615
1
vote
0
answers
441
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
2
votes
1
answer
170
views
Demonstrating molten oxide electrolysis on the Moon, what would require the most power, keeping it molten or driving the electrolysis?
It seems that oxygen may be extractable from oxides in lunar regolith using "some variant of the" molten oxide electrolysis.
Assuming that solar energy is used in a lunar setting, what would ...
- 149k
3
votes
1
answer
69
views
How to predict reaction of propellants at chamber temperature and pressure? [duplicate]
I would like to understand how to calculate the complete reaction of propellants at chamber temperature and pressure.
For instance taking ethyl alcohol (75%) and LOX combustion with mixture ratio of 1....
- 43
4
votes
1
answer
513
views
Why might krypton have a lower utilization fraction than xenon for ion propulsion, and what can be done to improve it?
A comment below Why will Starlink satellites use krypton instead of xenon for electric propulsion? links to the 2011 preprint A Performance Comparison of Xenon and KryptonPropellant on an SPT-100 Hall ...
- 149k
8
votes
2
answers
489
views
Sabatier reaction oxygen to methane ratio for Mars ascent propellant
The Sabatier reaction is as follows:
$$\mathrm{CO_2 + 4\: H_2 \rightarrow CH_4 + 2\: H_2O}.$$
If water is electrolysed
$$\mathrm{2\:H_2O \rightarrow 2\: H_2 + O_2}$$
the global reaction becomes
$$...
- 387
8
votes
3
answers
3k
views
Have light gases like hydrogen or helium been explored for ion propulsion?
This answer and discussion in comments below this answer mention that for an ion of mass $m$ and charge $q$ accelerated by a voltage $V$ the momentum it receives (impulse) is
$$p = \sqrt{2mqV} = \...
- 149k
1
vote
0
answers
69
views
What is the most efficient way to go to Titan? [closed]
With ionic motors? or chemical engines? liquid propellant (LH2) or gas? What is the most compact way to make the trip? in the smallest possible rocket, for example the SS-520-5 is a 2-stage rocket, 11....
- 1,623
3
votes
3
answers
460
views
Is there any practical application of trinitramide N(NO2)3 in rocket propellants
In 2010 researchers at the Royal Institute of Technology (KTH) in Sweden announced the discovery of new compound, trinitramide N(NO2)3, which could revolutionize production of solid rocket propellants....
- 2,331
0
votes
1
answer
125
views
Is it possible for aluminium alloys in a explosion in space or on earth to become pure elemental powder particles? [closed]
If you have some kind of explosion, is it then possible for aluminium alloys to become powder particles?, is yes, can they become pure elemental aluminium particles?, or will they always be aluminium ...
1
vote
0
answers
41
views
How can 3He be mined on the moon? [duplicate]
Now I know how it is detected, but what would the mining process be like? given that there is a lot on the moon but not concentrated, so you have to process large amounts of surface to extract a ...
- 1,623
4
votes
0
answers
70
views
Hydrocarbons of Titan: Potential Applications
Imagine in the future that some space agency or corporation has deployed a manned mission to Saturn's moon Titan with the intent of collecting samples of its hydrocarbons. This is to be accomplished ...
- 161
3
votes
1
answer
686
views
Are Mars' atmospheric CO₂, O₂ and CO in equilibrium? Are sunlight or chemical reactions involved?
According to the NASA JPL video linked below the top five gases comprising the martian atmosphere include CO₂, O₂ and CO. Do the proportions reflect some chemical equilibrium? Are sunlight or chemical ...
- 149k
1
vote
1
answer
459
views
What is a lithium fed GIT? How does it work?
This answer to What is the maximum speed an ion engine can propel a spacecraft at? mentions the following:
Lithium fed GIT (gridded ion thrusters) have demonstrated 50,000 - 80,000 seconds of ISP (...
- 149k
4
votes
1
answer
936
views
Which scientific articles together give proof of all the chemical elements found on Mars?
Wikipedia about the elemental composition of Mars:
Based on these data sources, scientists think that the most abundant chemical elements in the Martian crust, besides silicon and oxygen, are iron, ...
- 7,551
4
votes
1
answer
585
views
Are there fuel cells for methane + oxygen? Could there be?
Hydrogen + oxygen fuel cells powered the week-long Apollo missions to the Moon and Shuttle missions to orbit, and there is a industry trying to build itself around hydrogen-fed fuel cell-based road ...
- 149k
1
vote
1
answer
96
views
What is the heaviest chemical element that has been recovered from beyond cis-lunar space? [closed]
Material has come to Earth from deep space (beyond cis-linar) and been subjected to scientific analysis both in the form of meteorites, and via robotic sample collection spacecraft and robotic ...
- 111