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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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9 votes
1 answer
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Why alcohol had been selected as fuel for the first American space rockets?

I was surprised to read that Redstone used 75% ethyl alcohol as a fuel. Looks like this idea was abandoned later, and modern rockets use rectified petroleum or liquid hydrogen instead for burning with ...
Nightrider's user avatar
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25 votes
1 answer
8k views

What "fuel more powerful than anything the West (had) in stock" put Laika in orbit aboard Sputnik 2?

The BBC World Service Radio Witness History podcast Laika, the first dog in space contains a short audio clips from some vintage 1950's British news. At 02:30 in a ...
uhoh's user avatar
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5 votes
1 answer
1k views

Why can't an expander-cycle engine be built to use RP-1 or other non-cryogenic fuels?

The expander cycle family of rocket-engine power cycles involve using waste heat from the engine's combustion chamber and/or nozzle to vapourise some or all of the engine's fuel, and using the now-...
Vikki's user avatar
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4 votes
1 answer
602 views

How were hypergolic propellants delivered to the Shuttle launch pad?

The Space Shuttle Main Engines used cryogenic hydrogen and oxygen, and this question explains how those were supplied to the launch pad. But the OMS and RCS engines used hypergolic fuels. How were ...
DrSheldon's user avatar
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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 ...
InkWiring's user avatar
9 votes
1 answer
1k views

Are rocket engine feed pipes flexible?

Let's restrict this question to rockets whose first stage : run on liquid propellant use turbopump (this may be too restrictive for this question, but it still restrict to many rockets in use today -...
Manu H's user avatar
  • 3,790
6 votes
1 answer
739 views

Are the APUs on the SLS SRBs planned to be hydrazine powered?

I recently read that the Space Launch System core stage, which uses renamed / slightly reworked Space Shuttle Main Engines and therefore requires a hydraulic system to service said engines, will use ...
Organic Marble's user avatar
8 votes
2 answers
2k views

How does one "dump" or deplete propellant without changing spacecraft attitude or trajectory?

Occasionally one reads about a spacecraft "dumping fuel". It may mean expelling the propellant(s) as a liquid, or depleting them by burning them up. Although usually only fuel is mentioned, often ...
DrSheldon's user avatar
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14 votes
1 answer
2k views

What happened to boiled-off gases from the storage tanks at Launch Complex 39?

Both Apollo and the Shuttle launched from KSC complex 39, and used liquid oxygen and liquid hydrogen as propellants. These cryogenic liquids were held in storage tanks near the perimeter of each ...
DrSheldon's user avatar
  • 48k
1 vote
1 answer
623 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 ...
Putvi's user avatar
  • 143
1 vote
0 answers
261 views

How does the inter-propellant seal works in kerosene/LOX and UDMH/NTO rockets?

I get that the inter-propellant seal on the SSME LOX HP pump is simply a series of cascading regular seals trying to eliminate bleed-through by venting and letting boil at each stage, so that when ...
Meatball Princess's user avatar
21 votes
2 answers
23k views

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 ...
uhoh's user avatar
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4 votes
1 answer
277 views

Why is LOX on top in the Space Shuttle external tank instead of the other the way round? [duplicate]

Why is oxygen placed on top of hydrogen? Does this have anything to do with letting the warmer and not the colder liquid have a non-spherical bulkhead and thus more surface area to reduce boil-off?
Meatball Princess's user avatar
9 votes
1 answer
1k views

Why did the Americans abandon kerosene after F-1 while the Soviets continued to develop it to very high sophistication?

What is the reason behind America's switch to LH2/LOX, and (USSR's) Russia's decision to stay with it and develop it to spectacular technical sophistication such as the Oxygen-rich staged combustion ...
Meatball Princess's user avatar
4 votes
1 answer
461 views

Is Cryogenic Rocket Fuel Still Liquid When It Flows Through a Regeneratively-Cooled Nozzle?

For a rocket engine that runs on (deeply) cryogenic fuel like LH2, e.g. SSME, is the fuel kept liquid throughout the entire length of the regenerative cooling circuit in the nozzle? Or is it allowed ...
Meatball Princess's user avatar
4 votes
2 answers
550 views

How could a hydrazine and N2O4 cloud (or it's reactants) show up in weather radar?

Question: How could a hydrazine and N2O4 cloud (or it's reactants) show up in weather radar? Tweet: This is what an ‘anomaly’ looks like on weather radar. Tweet (with GIF): Dragon's static fire ...
uhoh's user avatar
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13 votes
2 answers
3k views

Can a rocket refuel on Mars from water?

Can a rocket run only on hydrogen and oxygen? Could a rocket, rover, and electrolysis machine be sent to either of Mars' poles to excavate ice to make hydrogen and oxygen to refuel an unmanned rocket? ...
Muze's user avatar
  • 1
2 votes
1 answer
131 views

How to find an optimal number of propellent tanks?

My idea: If the propellent mass to tank mass ratio remains constant when increasing/decreasing the amount of propellant then you could increase $\sum \Delta v$, by splitting the propellent tank and ...
user avatar
2 votes
2 answers
382 views

Break Away Valves for Launch [duplicate]

I forgot to hang up the fuel pump and broke it off and costed around 80 dollars to replace. While there I wandered could this be adapted to a rocket in some way? How much fuel capacity would be saved ...
Muze's user avatar
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5 votes
1 answer
614 views

What rocket system launch contained the highest amount of propellent potential energy?

In regards to rocket launches, what rocket launch contained the most potential energy (joules/btu/etc.) in its thrust propellant to achieve is basic mission? I'm not as much concerned with ...
Milwrdfan's user avatar
  • 2,798
25 votes
7 answers
6k views

Pre-mixing cryogenic fuels and using only one fuel tank

A methalox engine is fed from two cryogenic fuel tanks. Why can't the methane and oxygen be mixed as gases, in the desired proportions, and then chilled to a temp that liquefies both? From a single ...
SpaceInMyHead's user avatar
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 ...
Sdarb's user avatar
  • 317
17 votes
1 answer
1k views

How much propellant is used up until liftoff?

How much of the total propellant mass (fuel+oxidizer) of the first stage/boosters is usually burnt between ignition and liftoff?
Everyday Astronaut's user avatar
1 vote
1 answer
216 views

Fuel vs food on the trip to Mars?

How much food for each person is need and fuel per various engine to go to Mars on the current 9-month trip there then 3 months on Mars and the 9 months back? Can time be saved on the trip to and from ...
Muze's user avatar
  • 1
0 votes
1 answer
150 views

What are ways to store hydrogen for electric propulsion without a heavy pressure vessel?

This comment points out that any advantages of using low-mass ionized atomic hydrogen (i.e. protons) for electric propulsion if you had a fixed acceleration voltage and plenty of electrical power ...
uhoh's user avatar
  • 149k
2 votes
1 answer
148 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 ...
Greg's user avatar
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4 votes
1 answer
457 views

What type of propellant does Spacex plan to use in Starship for long duration missions?

For long duration missions such as ones to mars what type of propellant would be best suited?
Josh Jagessar's user avatar
7 votes
2 answers
3k views

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 ...
AndrewMaxwellRockets's user avatar
5 votes
1 answer
327 views

Are there any hypergolic solid/liquid fuel combinations?

Could the principal of hypergolic fuels be applied to hybrid rockets? And if so, are there any known hypergolic solid/liquid combinations?
Edward Jane's user avatar
0 votes
1 answer
81 views

Scoutleader looking for understanding of fuel burn for getting away from earth gravity Vs. fuel expended when traveling from A-B in space

I am a layman scoutleader and like to discuss the amount of fuel needed to get from earths gravity to the thrust needed in space to get from A-B. Is there a spreadsheet that would give course ...
Kevin Bibeault's user avatar
5 votes
1 answer
287 views

What methods are proposed for storing cryogenic fuels (esp. hydrogen) in space for months or years?

Current Launch vehicles and upper stages must only keep their fuels for minutes or hours, so they are only insulated to keep boiloff to a few % per day - I've seen 21% per day quoted for Centaur on ...
Talisker's user avatar
  • 352
4 votes
1 answer
2k views

Why doesn't the Merlin 1-D use higher LOX to RP-1 mixture ratios?

So I've been screwing around with CEARUN, which is the chemical equilibrium with applications program created by NASA. I've been using it to calculate theoretical Isps for rocket engines using RP-1 ...
chuckstables's user avatar
6 votes
3 answers
310 views

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.
user28833's user avatar
  • 499
5 votes
0 answers
130 views

What fuels would make refueling in space more dangerous/complicated?

I saw the question: Has in-space refueling been done? And was actually beginning to wonder, is refueling and transferring propellant dangerous in space? I understand that this would most likely be ...
Magic Octopus Urn's user avatar
11 votes
1 answer
3k views

Was there fuel consumption budgeting for Apollo 11 Lunar module?

Did the astronauts aboard Apollo 11's Lunar Module have any stated or imposed limitation or restriction on the amount of fuel they could use while in lunar orbit and performing landing maneuvers? I am ...
Niranjan's user avatar
  • 3,796
5 votes
2 answers
5k views

What are some notable cold gas thruster propellants, and why?

Cold gas thrusters are a very simple and reliable form of thruster that operate only by spraying a compressed gas, without any chemical reaction. What are the most common, performant, or otherwise ...
charliegreen's user avatar
6 votes
1 answer
1k views

Falcon 9: how much fuel is left on a booster after stage separation?

If the booster attempts either land or sea landing, how much fuel (RP-1 and LOX) is left in its tanks right after stage separation? Recently, I have heard numbers as high as 30% of its total tank ...
Everyday Astronaut's user avatar
11 votes
1 answer
16k views

How much fuel does the Falcon Heavy use? What is the price RP-1?

Does anyone know how much fuel the Falcon Heavy can hold, the RP-1 fuel and liquid oxygen as oxidizer, and how much of that will it use to get to a certain point? I don't know how i would calculate ...
Pjotr's user avatar
  • 175
10 votes
1 answer
1k views

Why did the MarCO space probes use fire extinguishant as their propellant?

In many news articles, it's mentioned that the MarCO spacecraft, launched with InSight, used fire extinguishant as the propellant for its cold gas thrusters. I originally assumed that this was ...
charliegreen's user avatar
4 votes
2 answers
205 views

Propellants used for different Mars landers [till 2018]

What propellants have been used by lander to land on Mars surface?
Vasanth C's user avatar
  • 1,161
4 votes
0 answers
499 views

Does the pressurization of tanks prevent "liquid sloshing" during maneuvers?

I'll be the first to admit I know little to nothing about fluid dynamics, especially in a pressure vessel. I was wondering how pressurized rocket fuel tanks don't cause weight-distribution problems ...
Magic Octopus Urn's user avatar
4 votes
0 answers
110 views

How much fuel is left in InSight?

InSight probably landed with some fuel margin. Unless it was vented/burned on landing (maybe not a bad idea considering potential leaks down the road), is there some left ? Do we know the ISP of ...
Antzi's user avatar
  • 12.7k
2 votes
1 answer
186 views

What could be the proprietary propellant blend that "Apollo Fusion" claims to have developed for it's hall effect thrusters?

According to the info posted on the Apollo fusion website http://apollofusion.com/ , they claim to use a propellant blend that offers " 2-3 X more impulse per mass and volume" in comparison towards ...
Amongdastarz's user avatar
3 votes
2 answers
844 views

How much fuel to maintain VLEO for communication satelites?

A recent answer about communication satellites in VLEO (≤350 km) estimates a useful orbital life of about month without fuel. I.e. Once the vehicle is out of fuel to maintain orbit, THEN it has the ...
James Jenkins's user avatar
8 votes
1 answer
3k views

What percentage of overall fuel does a rocket burn up to get to max-q?

I know that max-q normally occurs around 11-15km (based on observations of watching falcon 9 launches and this). Furthermore, I know that the fuel usage for each rocket would vary a lot (which I ...
Vivek's user avatar
  • 658
5 votes
1 answer
470 views

Insulation used in the plumbing line of the actual rockets

While using the pipes for plumbing of the liquid propellants at pretty low temperature because of which ice form on the line if not insulated or poorly insulated, which can lead to liquid to gas ...
Amar's user avatar
  • 2,246
19 votes
1 answer
2k views

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 ...
uhoh's user avatar
  • 149k
2 votes
0 answers
86 views

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.
ARK's user avatar
  • 21
13 votes
3 answers
3k views

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 ...
Steve Linton's user avatar
  • 19.6k
6 votes
1 answer
756 views

Curves on Isp/density chart, what varies along each curve?

In an answer to this question, the brilliant diagram below was given: Each fuel has a similarly shaped curve on the chart. What does that signify? what varies along the curve?
Steve Linton's user avatar
  • 19.6k

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