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Questions tagged [fuel]

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

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8 views

What's the highest ISP that a chemical rocket has achieved without using propellants maintained at cryogenic temperatures?

This is related to my earlier question about capturing an asteroid. If you wanted to place an interceptor rocket in space and the purpose of that rocket is to wait for a long time, and then launch to ...
-2 votes
1 answer
166 views

Late 19th century rocket design [duplicate]

Would it have been possible to build a moon rocket in the 19th century using then-existing technology? In 1890s France, Pedro Paulet supposedly tested a small liquid-fueled rocket using dinitrogen ...
4 votes
1 answer
216 views

Would that asteroid transport be possible?

I did the mistake of watching an episode of the Science Fiction series "For All Mankind". There they are trying to catch an asteroid in order to bring it back to Mars. I know this series is ...
3 votes
0 answers
188 views

Does Starship run on Slushies?

Cryogenic slush (a mixture of liquid and solid) can potentially store propellants at higher density than cryogenic liquid. For instance, hydrogen slush is 16-20% denser than liquid hydrogen. https://...
6 votes
1 answer
2k views

What "green" propellant powers Curie, the engine on RocketLab's payload kickstage?

Upon news of RocketLab's successful flight of the Electron launch vehicle, it was announced that not only had they deployed the three onboard payloads into the desired orbit, they had done so using a ...
4 votes
1 answer
199 views

Theoretical viability of a liquid rocket engine concept [closed]

[DISCLAIMER: I am an aerospace engineer undergrad and I do NOT want to build this. I wanted to come up with an alternative for the usual hypergolic mix so US military personnel would have one less ...
9 votes
2 answers
2k views

Is there any satellite that uses LOX as oxidizer?

With Liquid Oxygen being used as an Oxidizer in Starship and some other rocket engines, I was curious if LOX was also used for propelling satellites as well.
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 ...
9 votes
1 answer
709 views

How is SpaceX planning to avoid fuel sloshing on IFT3?

SpaceX is about launch IFT3 and during IFT2, the booster exploded probably due to sloshing and an engine having something block its fuel supply. What has SpaceX changed to avoid fuel sloshing?
9 votes
0 answers
242 views

What rocket uses the largest percentage of Fuel/Oxidizer before liftoff?

inspired by this question: How much propellant is used up until liftoff? which asks how much propellant (fuel/oxidizer) a typical rocket uses before liftoff. What has been or is the most non-typical ...
4 votes
2 answers
282 views

In principle, could the oxygen tanks of an 'air breathing' rocket, be filled during ascent?

(Thinking of SABRE and it's heat exchanger). As I understand it, Skylon would take off with full oxygen tanks. Putting aside engineering difficulties, is there a thermodynamic reason why a hybrid ...
18 votes
4 answers
7k views

What is the best chemical rocket fuel from a purely specific impulse standpoint?

A variety of different rocket programs use a variety of different fuel types. Researching this, the main fuel combinations I saw were: RP-1 / LOX (SpaceX's Falcon rockets, early stage Atlas and Saturn ...
14 votes
2 answers
2k views

Why is the Space Shuttle's External Tank fuelled through the Orbiter's main engine plumbing system?

This answer states that Space Shuttle's External Tank (ET) was fuelled (this process is known as Tanking) through the Orbiter's main engine plumbing system with the Tail Service Masts (TSM). One ...
10 votes
2 answers
2k views

Hydrazine and liquid fluorine as a semi-cryogenic storable lunar space propellant

The use of liquid fluorine as an oxidizer diluted with liquid oxygen has been tested, but wasn't flown, by Bell and Rocketdyne, seperately. http://www.astronautix.com/l/lf2hydrazine.html It was ...
-1 votes
1 answer
148 views

Propellant consumption of Starship trip from NRHO to Mars

People, I am trying to estimate the amount of propellant (liquid oxygen+ liquid methane) required by Starship to reach Mars from NRHO (Near-rectilinear halo orbit). Also the propellant consumption ...
10 votes
3 answers
5k views

Do larger rockets tend to have a better mass ratio due to the square cube law?

Do larger rockets tend to have a better mass ratio due to the square cube law? I mean, larger tanks have a better surface-to-volume ratio, so their weight-to-volume should be improved
3 votes
0 answers
73 views

Force Constant of liquid propellants, RP-1 >1200 kJ/kg

I am familiar with testing of the force constant for solid propellants using the closed bomb test. But what test method is used to obtain the force constant of liquid propellants? And is the force ...
2 votes
1 answer
229 views

Are there any storable non-hypergolic oxidizers?

Any list of bipropellant rocket fuels I've come across has oxidizers that are either cryogenic (liquid oxygen), hypergolic (nitric acid), or both (liquid fluorine). Are there any practical rocket ...
11 votes
4 answers
7k views

Do the flames from a rocket cast a shadow, and, more generally, does the rocket exhaust cast a shadow?

Also, would there be any difference between shadows cast by the exhaust from a rocket as opposed to the flame from a rocket?
0 votes
2 answers
418 views

Looking for figures for contemporary interstellar engine options

So I have already done... a lot of reading on this subject lately. A lot. You wouldn't believe. My maths is... functional, probably far above 'average', but when it gets into the realms of the 'rocket ...
-1 votes
1 answer
130 views

What should be the fuel mass of a hypersonic (Mach 7) rocket using APCP fuel that would deliver a 50 gram payload?

Well, I used this rocket calculator besides asking ChatGPT and BingGPT and both gave me similar answers where the amount of fuel would be around 300 to 4000 grams of APCP fuel. And 30 to 100 grams for ...
11 votes
1 answer
3k views

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 ...
8 votes
6 answers
3k views

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 ...
1 vote
0 answers
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What kind of propulsion did/does the Raytheon EKV vehicle use?

Raytheon has developed an Exoatmospheric Kill Vehicle, designed to intercept an ICBM and destroy it through a collision. Here are some related links: Wikipedia page YouTube video about the project, ...
13 votes
2 answers
3k views

Could a Mars rover go to Phobos or Deimos instead?

Could a Mars rover go to Phobos or Deimos instead of going to Mars? The choice is made after launch, and no further modifications can be made to the rover. Could it land safely? Up to what point could ...
7 votes
4 answers
5k views

Why is fuel cheap compared to rocket?

The fuel for a Falcon 9 (SpaceX) costs around \$200,000 per launch, while the launch itself costs \$62,000,000. Safety precautions, rocket shell and rocket engines cost a lot. But why not fuel?
1 vote
2 answers
331 views

Can hydrogen peroxide and propane be a good rocket propellant combination?

The decomposition of hydrogen peroxide can be used to spin the turbopump and then it can be mixed with propane in the combustion chamber
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51 views

Methane vs propane as rocket fuel [duplicate]

How would propane compare with methane as rocket fuel? Propane can also be stored as liquid under pressure.
3 votes
0 answers
78 views

Computing Flight Characteristics for Different Propellant Grain Geometries?

Consider the following image: I am interested in mathematically accounting for some of these different geometries but have had little success so far in finding how this can be done. The first thought ...
3 votes
1 answer
492 views

Which are more efficient: oxidizer-rich or fuel rich rocket engines?

Several internet articles claim that the high Isp of the Soviet RD-180 engine (as used in the Atlas III and V launch vehicles) was (at least partially) due to the fact the RD-180 ran oxidizer-rich, ...
-6 votes
1 answer
308 views

Hydrogen-propelled space elevator [closed]

I'm working on a space elevator design using kerosene-burning jet engines and dirigibles supporting 1km stages of pipeline and cable stretching up to the end of the stratosphere (~50km), then using ...
-4 votes
1 answer
235 views

How does SpaceX prevent fuel from cluttering together in zero G [closed]

What is the solution to stop fuel inside starship collecting in center of the tank during zero G flight? Here is a rough sketch of starship with rudimentary diaphragm system to control flow of fuel ...
2 votes
0 answers
88 views

Non-Cryogenic Propellant Transfer

I know there are programs like the Rocket Lab CryoSat, but I was wondering if there have been any tests of non-cryo propellant transfer? I know the Space Station refuels with a storable hypergol, but ...
0 votes
1 answer
95 views

Semi-Cryogenic HTP/LH2 engine?

Also see HTP as oxidizer for main propulsion (for more info on history of H2O2/HTP in rocketry) Note: HTP and H2O2 will be used interchangeably I know the Black Arrow LV (The first orbital lipstick) ...
1 vote
0 answers
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How do you find the burn-time of a specific solid rocket fuel?

I read this post about finding the propellant mass needed to reach a specific altitude: How do you find the propellant mass needed to reach an inputted altitude?(altitude at end of burn plus altitude ...
1 vote
2 answers
434 views

What would it take to collect methane from the atmosphere and use it as rocket fuel?

SpaceX is currently dealing with a lot of environmental regulation issues with Starship. One issue they have is the amount of CO2 Starship produces. Their falcon 9 produces 440 tons of CO2 each flight,...
2 votes
0 answers
68 views

What is the A in the mass flow rate formula for solid rocket propellants? How do I get the chamber pressure? [closed]

I believe the mass flow rate formula for solid rocket motors is:$$\dot{m}=p_pA_br$$ What is $A_b$ in this case. Is it the cross-sectional area of the hole in the grain? What is there is a nozzle? What ...
-10 votes
2 answers
771 views

Debunking Apollo 11 based on the fuel usage [duplicate]

I have checked the NASA docs and it says they needed hundred thousand liters of liquid hydrogen for the various stages of the Apollo 11 mission. For example stage 2 was calculated to need at least ...
1 vote
0 answers
54 views

Rough values for the staytime or characteristic length of the combustion chamber of an oxygen/methanol rocket engine?

I'd like to have some idea of the staytime or characteristic length of the combustion chamber of an oxygen/methanol rocket engine. Are there sources for this, or a way to estimate it? I've tried, but ...
3 votes
1 answer
664 views

Does this Soyuz vehicle burn coal or oil? What is its official name?

This tweet shows the image below and says: Soyuz rocket on its way to the launch pad (on a train of course). Question: Does this Soyuz vehicle (a train engine) burn coal or oil? Does it have an ...
5 votes
1 answer
325 views

Would reaching an elliptical orbit with the same mean altitude as that of a circular orbit require the same amount of fuel?

Would a rocket that wanted to reach an elliptical orbit with a perigee of 100 miles (160 km) and an apogee of 300 miles (480 km) burn the same amount of fuel as a rocket that wanted to attain a ...
3 votes
3 answers
4k views

Going over the Apollo fuel numbers and I have many questions

I was reading through Apollo by the numbers and I noticed the LM descent to the moons surface consumed 17,414kg of fuel out of a total of 18,184kg leaving only 770kg of fuel. But then in the very next ...
1 vote
1 answer
103 views

Multi-stage combustion products?

Okay so I've never seen anything about this before, and that's probably for a very obvious, very simple reason I am far too dim to think of, but here goes: Most combustion reactions in rocket chambers ...
4 votes
5 answers
603 views

Will mining water on Bennu for travelling to Mars not be more economical than mining 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 ...
1 vote
2 answers
163 views

Deep space mission propellant

For an interplanetary mission that has a duration of 40 years cam we use hydrogen peroxide monopropellants? Can we use arcjets?
2 votes
1 answer
143 views

Propellant choices for a Mars landing; tradeoffs between LOX/CH4 and H2O2/RP-1?

What are the tradeoffs between LOX/methane and peroxide/kerosene for a Mars landing mission? In which ways are each better or worse than the other? I think the second one would more attractive for ...
0 votes
0 answers
134 views

How to estimate the fuel required to send 1 kg to lower mars orbit?

Imagine a rocket with a payload of 1 kg. How much liquid fuel would be required to send that 1 kg payload to lower mars orbit. (1 kg is just the payload not the whole dry mass of the rocket) I want ...
22 votes
4 answers
4k views

How do space probes find their way and how much fuel do they use to travel?

How do space probes find their way, for example, to explore dangerous planets like Jupiter or Saturn that have powerful magnetic fields? Do scientists control it from stations in NASA or they have a ...
5 votes
1 answer
270 views

Why did the June 2016 SpaceX launch run out of propellant?

In other words, what caused SpaceX to miscalculate the amount of propellant required to safely land the booster. They had landed successfully on the drone ship in April. So what went wrong here? What ...
4 votes
0 answers
153 views

How was the external tank emptied in a TAL shuttle abort?

One of the numerous reasons RTLS was the least preferred choice is For a safe separation, the ET must contain a maximum of 2% propellant remaining at Main Engine Cutoff (MECO). How would TAL do away ...

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