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Questions tagged [fuel]

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

9
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6answers
960 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 ...
3
votes
0answers
36 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 ...
8
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1answer
974 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?
0
votes
1answer
102 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 ...
0
votes
1answer
76 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 ...
2
votes
1answer
42 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 ...
2
votes
1answer
151 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?
2
votes
2answers
243 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 ...
4
votes
1answer
66 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?
0
votes
1answer
55 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 ...
4
votes
1answer
131 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 ...
2
votes
1answer
69 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.
2
votes
0answers
74 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 ...
10
votes
1answer
2k 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 ...
1
vote
0answers
109 views

What is the best fuel for bottle rocket? [closed]

I want to modify my firework bottle rocket to fly a mile high. What will be the best fuel for this? Could fuel used in space rockets be scaled down to work in a large bottle rocket?
4
votes
2answers
208 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 ...
3
votes
0answers
57 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 ...
9
votes
1answer
2k 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 ...
6
votes
1answer
165 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 ...
4
votes
2answers
88 views

Propellants used for different Mars landers [till 2018]

What propellants have been used by lander to land on Mars surface?
3
votes
0answers
68 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 ...
4
votes
0answers
95 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 ...
2
votes
1answer
91 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 ...
3
votes
2answers
136 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 ...
8
votes
1answer
641 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 ...
5
votes
1answer
152 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 ...
3
votes
0answers
61 views

Pressurization line (Helium to LOX tank line) chilling while pressurizing LOX tank

I have read that in rockets and launch vehicles Helium is used for the pressurization of propellant tanks. What temperature Helium is stored at? If Helium is stored at room temperature then while ...
12
votes
1answer
504 views

Does the Soyuz spacecraft chemically stabilize the hydrogen peroxide (H2O2) to remain ISS-dockable for 200+ days?

Hydrogen peroxide from the local shop (dilute, 2-3%) sometimes has a stabilizer to slow it's breakdown rate and increase it's "shelf-life", since we'd like to keep it around the house on our shelf for ...
2
votes
0answers
56 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.
6
votes
1answer
467 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 ...
6
votes
1answer
222 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?
3
votes
2answers
101 views

Do military rockets use the same fuels as their civilian versions?

Some rocket families have been used for both military and civilian purposes (e.g. Atlas). Do the military versions use the same fuel as their civilian counterparts?
4
votes
1answer
162 views

How do they know how much liquid propellant is in a rocket just before launch?

In this answer I wrote: In other words, a few tons here or there could depend on something as simple as the weather, or trying to squeeze a little extra propellant in for a given mission with a ...
6
votes
1answer
422 views

Russian “kerosene” versus American “RP-1”

RP-1 rocket fuel is a "highly refined form of kerosene". Most of the literature I have seen refers to Russian rockets using kerosene, versus American rockets using RP-1 (*1). Is there really such a ...
32
votes
3answers
7k views

What is the primary reason for SpaceX motion to have astronauts board Dragon before fueling up the rocket?

News piece: NASA supports SpaceX plan to fuel rockets with astronauts on board. The move is criticized by many as unnecessarily dangerous. From what I understand though, it shouldn't be necessary - ...
6
votes
1answer
118 views

Is the atmosphere a positive or a negative for reusability?

Does the atmosphere provide a benefit or detriment in terms of fuel economy for rockets that take off and land back on Earth? We know that the atmosphere plays a large role in helping slow down ...
8
votes
2answers
2k views

Why do Ariane rockets not have ice break off on liftoff?

In a recent question asked here, it was asked what debris falling from a Rocket Lab Electron Rocket was during launch. e.g.: The answer, was that it was ice that had formed after cryogenic fuel/...
3
votes
1answer
77 views

Propellant filling rate in propellant tanks [closed]

I want to pump LOX into a pressure vessel at 2 bar (say). So for pumping it what should be safest flow rate?
4
votes
1answer
769 views

Vector-R's LP-1 and -2 engines use liquid propylene as fuel with LOX, advantages and distinctions from kerosene?

@gwally's answer highlights the company Vector Launch Inc. and their Vector-R rocket, which uses three LP-1 18,300 lbf engines on the first stage and one LP-2 1,000 lbf second stage engine to put ...
1
vote
0answers
41 views

Which is preferred for liquid atomization - gas & liquid shear or liquid & liquid shear?

For generating a spray of droplets, liquid need to be disintegrated/atomized through shear forces. Typical injectors in IC engines and aircraft use shear between gas & liquid at the phase ...
3
votes
1answer
124 views

What is the surrogate liquid for LOx during the preliminary testing of injectors?

Before transitioning to the LOx tests during any new injector development, water is typically used for calculating flow rates, pressure loss, etc. But testing with water cannot qualify as a suitable ...
2
votes
1answer
109 views

How are the Titan Transtage's tanks protected from its engine?

As a follow up to this answer which identifies the two pointed objects flanking the Titan Transtage's engine in an unusual configuration as its propellant tanks: How are these protected from the heat ...
0
votes
1answer
107 views

What is the Oxidiser/Fuel Ratio of the Atlas V Centaur Upper Stage?

I can't find this information anywhere for the single or double engine variant. could it be variable? Or is it a secret?
0
votes
1answer
107 views

Could the interaction of the Sun’s solar wind and trapped plasma ions be used to propel a rocket through interplanetary space?

I have recently had a renewed interest in comets and how comet tails are formed. From studying this process, a thought occurred to me that perhaps plasma ions can be created within a long hollow ...
13
votes
1answer
1k views

Why does the 2nd stage of Falcon 9 need compressed He tanks?

It is well known that the rapid disassembly of Falcon 9 static testing started with the rupture of the composite fibres of the copv He tanks. But what is the need to have the composite tanks ...
2
votes
1answer
77 views

Rocket engine power vs. Sound

Is there any relationship between the sound emitted from a rocket engine and the amount of thrust it gets at surface temperature and pressure?
5
votes
0answers
124 views

What is the droplet size that is desirable for pintle injectors?

The pintle injectors tend to generate droplets after impingement of the fuel and the oxidiser stream and I understand that the droplets will be premixed. In such a case, even a larger premixed ...
22
votes
1answer
2k views

Why is fuel ratio different for upper stage of a rocket?

After reviewing this amazing graphic posted in another question: I noticed that the LH/LOX ratio is slightly different in the Second and Third stages. The mass stoichiometry of the reaction: 2 H2 + ...
6
votes
2answers
105 views

How do you calculate what percent of hydrogen combustion is turned into heat vs pressure?

As a high school calculus and physics student interested in aerospace engineering, I was trying to understand the basics of how a rocket works and couldn’t find an equation or any analysis online on ...
5
votes
2answers
510 views

What are the energy-to-mass ratios of some fuels/oxidizers, when including the oxidizer?

Energy-to-weight ratio is an important parameter. We would like it to be high so we don't have to carry around much fuel. Maybe you've heard some of the numbers for common fuels. Hydrogen is about ...