Questions tagged [fuel]

Questions about rocket oxidizer, propellant, reactive mass, or other fuels used in spacecraft or rockets.

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120 views

How much easier is it, to explore space from a low orbit satellite, than from Earth?

Note: in this question I'm considering cost in both money and fuel terms, and looking for answers that consider both. So we know that using chemical rockets to reach the moon, or further into space, ...
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1answer
241 views

Does LOx stay as liquid when entering combustion chamber?

Given the heat from combustion and increased temperature, would the LOx still be in liquid form after emanating from the injector? Or will it instantly transform into gas? Are injectors cooled using ...
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Methane internal combustion engines for rovers on Mars and Moon. Feasibility?

It seems possible to produce methane and oxygen from the atmospheric CO2 and icy soil on Mars, and from icy regolith in the polar craters of the Moon. It has been suggested that CH4+O2 could be used ...
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485 views

Use of high energy propellants on an engine designed for low energy propellants

This question is about use of high energy propellants on a rocket engine designed for low energy propellants. In any engine, which is currently working on RP1+LOX, if we change the fuel from RP1 to ...
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Why will Starlink satellites use krypton instead of xenon for electric propulsion?

The press kit for the first Falcon 9 Starlink launch and deployment of the first 60 satllites scheduled for May 15, 2019 says: With a flat-panel design featuring multiple high-throughput antennas ...
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Why don't rockets use propane?

Most BBQs use propane. Propane burns quite well and it is quite clean. So why hasn't anyone use it as a rocket fuel??
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123 views

In situ Fuel in LEO / MEO

I have been thinking on controlled de-orbiting of Satellites. You can carry a supply of conventional chemical fuel, and use it to apply a delta-V that would de-orbit them. There are also methods of ...
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292 views

Will mining water on Bennu not be more economical than collecting it at the lunar south pole?

Bennu is a carbonaceous asteroid that is currently accompanied by the OSIRIS-REx spacecraft that will take samples from it to return to Earth. Its diameter is 490 m. and it is slightly denser than ...
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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 ...
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Alternative propellants in nuclear thermal rockets

Many years ago, I read a science fiction story "Rocket Ship Galileo" in which a nuclear powered spacecraft used zinc as a propellant. Apart from the fanciful nature of the story itself, I ...
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205 views

How much fuel could a rocket save by launching from an airship/blimp?

What could the Kozlov’s Aerosmena project blimp add to fuel saving if space rockets were launched from it? Where would you place the rocket and airship on this chart?
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What is the formula to calculate how much fuel is needed for a rocket?

I'm theoretically trying to launch a rocket for a school project and therefore I chose Saturn V. I took its weight of 140.000kg (308 647 pounds) and I'm trying to calculate how much fuel it'd take to ...
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Why RP-1 and not Methane for Falcon 9's Merlin engines?

I've seen methane described as the best of both worlds---the worlds being hydrogen's energy density + pain-in-the-ass factor and RP-1's lower energy density + ... ease of use? And this has me ...
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energy needed to accelerate in space

I was thinking about possibility of cargo transport between, say, earth and mars when a “pusher” accelerates propulsion-less cargo vessel, which is catched and decelerated at the other end of ...
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Can Pyroxene and other silicon compound be used as a theoretical spacecraft fuel?

I have been reading this patent : https://patents.google.com/patent/US3137599A/en This lead me to this paper: https://www.jstor.org/stable/44682837?seq=1 The first uses Polysilane, which basically ...
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SpaceX Dragon: How many fuel tanks?

I've read that Dragon carries 1380 kg of MMH + NTO propellant. This mass would be split among the various tanks, and I'm wondering---how many of them are there? Pictures from the manufacturing floor ...
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Why is hydrogen better than helium as remass?

I just watched a very good YouTube video on why nuclear engines might be useful, and it also goes into why Hall Effect thrusters are super good at squeezing obscene ISP out of things. During the video,...
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Is CO + O ==> CO2 a possibility for propelling rockets off Mars? [duplicate]

Perseverance, the Mars rover, includes an experiment called MOXIE. This is a technology demonstration to show that Mars' atmospheric carbon dioxide can be broken into carbon monoxide and oxygen. ...
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Why is an inflatable balloon inside a fuel tank not used to prevent fuel from “sloshing around”?

After seeing all the Starship failures, having something with a membrane keep things in place seems like an obvious solution. Has it been considered or tested - or do we simply lack a material that is ...
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How do you reliably blow up a rocket that was built not to explode?

NASA, and I'd imagine most space agencies around the world, demands abort systems of its commercial partners capable of destroying a rocket should it venture too close to populated areas. Note that ...
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When has hydrogen peroxide been used in rocketry?

Peroxide is apparently a very good propellant, but I can't seem to find any instance of it being used. Has it ever been used and if not, why hasn't it? What's its downsides?
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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. ...
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Could another fuel be used in the SpaceX Starship header tank?

A memory of hexane and water in a separatory funnel brought to mind the issue of helium and LNG in the header tank while the Starship flips and does its powered landing. There was discussion of the ...
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Is it correct that the Saturn V RP1 tank was pressurized by high pressure helium and the LOX tanks were pressurised by oxygen?

I understand from many sites that in the first stage of the Saturn V, the RP1 tank was pressurized by high pressure Helium tanks, but the LOX tanks were pressurized using gaseous oxygen. Is this ...
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Is it feasible to take liquid Helium in a Pressure Fed System?

Can liquid Helium be flowed through a heat exhanger to increase its temperature and pressure which will further pressurize fuel-oxidizer tanks.
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1answer
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Is there any way to get better performance from an NTR with non-H2 propellant?

Related: Is there some fundamental limitation that would prevent steam-powered rockets from reaching space? Thermal rockets, including nuclear thermal rockets, work best with minimal molecular weight ...
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Hydrocarbon + Nitrous Oxide: Is this a “friendly” alternative propellant system to hydrazine and NTO?

Even if you don't care about hypergolicity, there's the serious problem that most storeable chemical fuels are either horrifically toxic (like N2O4), dangerously unstable (like high-test peroxide), or ...
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Will you be having rubber or wax with your peroxide? (hybrid engine fuel tradeoffs)

Hybrid engines offer some practical advantages and some budgetary ones that can offset lower ISP, including potentially safer solid fuel to store and non cryogenic storage of some oxidizers like ...
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1answer
84 views

Which fuel cell fuels have been demonstrated in space?

Combination of fuel cells and electric motors - whether it has been used as part of an electric pump-fed cycles? gives a short summary of fuel cells and lists the following energy-containing fuels ...
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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 ...
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Potential Fusion Drive system calculation issue

I will start off by saying that this is an entirely hypothetical drive system with plenty of handwaving and optimistic physics. My question I think is fairly simple and may just be something that ...
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What is the O/F ratio of ethanolamine/H2O2?

I've just read this question What is the products of a catalyzed reaction between Hydrogen Peroxide and Ethanolamine with Copper(II) Chloride? and although its a very good question and an excellent ...
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Hypergolic Propellant Combination

Is Rocket Grade Hydrogen Peroxide and Liquid Hydrogen a hypergolic propellant combination? I recall, seeing the combination somewhere on the www, however I couldn't retrace the source where I saw it.
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590 views

What is the MXP-351 storable bipropellant?

Masten Space Systems has a proprietary hypergolic bipropellant called MXP-351 intended for use in the XL-1 lunar lander. We seem to know the following information: Non-cryogenic, with storage life of ...
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1answer
459 views

Does peroxide spontaneously decompose when introduced into hot combustion chambers?

I understand that hydrogen peroxide (HTP) can be decomposed into superheated steam and oxygen using a catalyst, but I haven't been able to find any information on whether or not it will decompose in ...
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Have there been rocket engines designed for diesel? What ISP theoretically possible?

Have there been rocket engines or even test engines that have used diesel as a fuel? If so, what oxidizer had they used and what ISP did they achieve? If not, is it possible to say what ISP is at ...
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1answer
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Does the Soyuz spacecraft use chemically stabilized hydrogen peroxide (H₂O₂) to remain ISS-dockable for 200+ days?

Hydrogen peroxide (H2O2) from the local shop (dilute, 2-3%) sometimes has a stabilizer to slow its breakdown rate and increase its "shelf-life", since we'd like to keep it around the house on our ...
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1answer
369 views

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

While searching the internet for designs on liquid fueled rocket engines, I noticed that some bottles of liquid oxygen say they contain some percentage of hydrogen peroxide. Could that be used as an ...
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Longest continuous burning chemical rocket engine?

I'm curious as to what rocket engine in a launched rocket burned the longest in a continuous fashion. I'm not interested in testing burns or inter-planetary engines which are designed for low-thrust ...
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Why do pressure-fed systems have to be pressurized with helium or nitrogen?

This is something I just don't understand. The way I see it, propellant can be pressurized all on its own in the tank. Just pump a lot of the stuff in there and make sure the tank is strong enough. ...
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1answer
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Limit to reduction of G-forces during reentry?

I was wondering whether there is a limit to the amount in which the perceived g-forces during atmospheric reentry can be reduced by trading fuel consumption for smoothed out deceleration peaks. To ...
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2answers
213 views

What happened to tripropellant rockets?

IIRC, tripropellant rockets can deliver superior performance compared to bipropellant rockets (at the cost of added complexity). Now, I know that there is the Li/H/F combo, but it isn't used because ...
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1answer
76 views

How do I calculate thermochemical properties of mixed gases?

I'm working on a rocket project, and my design of engines is stalled. I need to be able to calculate the Cp, Cv, and R for mixtures of O2/CH4 (stoichiometric or fuel-rich mix) and CO2/H2O (result of ...
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Have any rocket fuel systems actually been explosive, and could have detonated proper?

Never mind that this is the 18th question to have the rocket-explosion tag. To the question "Would the Dragon escape pod have survived this event?" asked about the AMOS-6 mission, Elon Musk ...
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1answer
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How much power do radiation-based engines produce

I heard that the Voyager satellites used a radioactive source to power the computer and sensor systems. How much power can this technique produce nowadays? Could it power, say, a fighting robot? ...
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2k views

Amount of fuel for accelerating a spaceship

Suppose I have a spaceship and fire up its engines, accelerating to 10000 km / h. Now I turn off my engine and see I have consumed 10 % of my fuel (90 % left). How much fuel does it take to ...
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808 views

At what travel distances are ion engines faster and more efficient than conventional fuel engines?

According to Scientific American (February 2009), ion engines start off slow, but build up speed as they travel. At what travel distance would an ion engine (such as an ion thruster, a Hall thruster, ...
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Cheapest rocket to go to space?

Have you ever heard of the old movie Salvage? The TV movie, “Salvage,” aired on January 20, 1979. The film begins with Harry successfully bidding for a vintage bi-plane and then reselling it in pieces ...
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What is the practicality of using sub-cooled propane in combination with HTP in an amateur engine design? [closed]

Using sub-cooled propane, at approximately -90°C (b.p. -42°C at STP) in combination with >80% hydrogen peroxide, can any meaningful gains be made, whilst considering that this fuel mixture would be ...
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Why is ethylene (ethene) not considered as a rocket fuel

In an answer to this question, the brilliant diagram below was given: The chart makes chilled ethylene look like a very appealing choice, yet I don't believe it is ever used. Why not? Edit: I just ...

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