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Questions tagged [chemistry]

Questions regarding the application of chemistry in space exploration, for example the composition of rocket propellants.

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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 ...
DYNAMIC AEROSPACE's user avatar
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 ...
Robert Goddard-Wright's user avatar
2 votes
2 answers
148 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 ...
Michael Bonnet's user avatar
1 vote
0 answers
132 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 (...
Tom Smith's user avatar
3 votes
1 answer
231 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 ...
DrZ214's user avatar
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1 vote
2 answers
97 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 ...
AnarchoEngineer's user avatar
6 votes
2 answers
256 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. ...
Koon W's user avatar
  • 263
0 votes
1 answer
154 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 ...
SE - stop firing the good guys's user avatar
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 ...
SE - stop firing the good guys's user avatar
3 votes
0 answers
203 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 ...
quinnkenri's user avatar
  • 1,130
3 votes
1 answer
361 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 ...
Florian Cabot's user avatar
3 votes
2 answers
138 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.
Ethan's user avatar
  • 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. ...
Ashvin's user avatar
  • 2,888
6 votes
1 answer
478 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 ...
R. Hall's user avatar
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2 votes
1 answer
177 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 ...
uhoh's user avatar
  • 149k
8 votes
1 answer
618 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 ...
Fred's user avatar
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9 votes
1 answer
332 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 ...
uhoh's user avatar
  • 149k
18 votes
2 answers
2k 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 ...
uhoh's user avatar
  • 149k
4 votes
1 answer
296 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 ...
uhoh's user avatar
  • 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 ...
uhoh's user avatar
  • 149k
3 votes
2 answers
256 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 ...
Sean's user avatar
  • 213
3 votes
1 answer
217 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 ...
uhoh's user avatar
  • 149k
11 votes
1 answer
325 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 ...
uhoh's user avatar
  • 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. ...
DodoDude700's user avatar
4 votes
1 answer
245 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 ...
Enzo's user avatar
  • 51
4 votes
1 answer
182 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 ...
uhoh's user avatar
  • 149k
3 votes
1 answer
311 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 ...
DodoDude700's user avatar
4 votes
0 answers
261 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 ...
uhoh's user avatar
  • 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 ...
uhoh's user avatar
  • 149k
2 votes
1 answer
178 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 ...
Ruben's user avatar
  • 1,154
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: (...
John Ortiz's user avatar
12 votes
3 answers
908 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 ...
Oscar Lanzi's user avatar
  • 8,525
1 vote
0 answers
428 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 ...
sara nabil's user avatar
2 votes
1 answer
161 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 ...
uhoh's user avatar
  • 149k
3 votes
1 answer
66 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....
Toshith 's user avatar
4 votes
1 answer
494 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 ...
uhoh's user avatar
  • 149k
8 votes
2 answers
487 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 $$...
Jak's user avatar
  • 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} = \...
uhoh's user avatar
  • 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....
Valentino Zaffrani's user avatar
3 votes
3 answers
444 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....
WOW 6EQUJ5's user avatar
  • 2,321
0 votes
1 answer
124 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 ...
Andy Ljunggren's user avatar
1 vote
0 answers
40 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 ...
Valentino Zaffrani's user avatar
4 votes
0 answers
64 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 ...
Jem's user avatar
  • 161
3 votes
1 answer
655 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 ...
uhoh's user avatar
  • 149k
1 vote
1 answer
455 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 (...
uhoh's user avatar
  • 149k
4 votes
1 answer
905 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, ...
Cornelis's user avatar
  • 7,535
4 votes
1 answer
574 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 ...
uhoh's user avatar
  • 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 ...
nexoma's user avatar
  • 111
4 votes
3 answers
450 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?
Bob Bailey's user avatar
5 votes
1 answer
357 views

Are rocket fuels and LOX pure or are there additives?

I wonder whether there are any small amounts of additives in rocket fuels such as hydrogen and kerosene, or to the liquid oxygen, or if they are absolutely pure (barring any unintentional ...
LocalFluff's user avatar