Questions tagged [fuel]
Questions about rocket oxidizer, propellant, reactive mass, or other fuels used in spacecraft or rockets.
223 questions
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2answers
77 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
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0answers
44 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
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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 ...
4
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0answers
104 views
+100
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
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2answers
83 views
Propellants used for different Mars landers [till 2018]
What propellants have been used by lander to land on Mars surface?
3
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0answers
58 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
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0answers
90 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 ...
1
vote
0answers
44 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
90 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
579 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
136 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
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0answers
57 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 ...
11
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1answer
396 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
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0answers
54 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
336 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
157 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
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2answers
99 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
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1answer
136 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
340 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
116 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 ...
7
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
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1answer
74 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
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1answer
491 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 ...
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0answers
37 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
111 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
101 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
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1answer
80 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
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1answer
98 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 ...
12
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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
70 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
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0answers
106 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
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1answer
1k 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
99 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
456 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 ...
8
votes
1answer
277 views
InSight Launch - Centaur Fuel Rich
During the launch of InSight today one thing sprung out to me: at T+408s the voiceover announces:
Centaur slightly fuel rich.
And again at ...
6
votes
2answers
226 views
Safety regulations for storing, handling, and using rocket fuels?
How does a company with no experience in space (like SpaceX or Blue Origin) find out how to safely handle hazardous and flammable fuels?
Are there safety regulations for how to store, handle, and ...
3
votes
2answers
97 views
Remaining fuel estimation/measuring Strategy in a spacecraft
During descent of a spacecraft to any planetary body the spacecraft uses retro engine with variable throttle to reduce the vehicle velocity to zero at touchdown.
Inorder to compute for the amount of ...
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0answers
94 views
Are there any situations where hot rather than cold propellants might be advantageous?
Given that cryogenic fuel and oxidisers exist, I wonder if the reverse is workable.
Are there fuels or oxidisers that have been considered for rockets that must be kept hot to be usable? By hot I ...
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0answers
120 views
How to size Solar Array for Mars Surface
Good morning everyone,
I am working on a project for my university where we need to perform a PrePhase A study for a Mars Infrastructure for Propellant production as a means of support for future ...
5
votes
2answers
199 views
Pro/cons of burning propellant in stochiometric ratio?
Several questions and answers here speak of stochiometric ratio. I do understand it is convinient for efficiency (greater ISP). I also read somewhere (I am unable ro find again the reference, it was ...
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0answers
54 views
Is fuel tank pressure structurally important? [duplicate]
Being super lightweight structures, do rockets depend to some degree on internal pressure of their fuel tanks for structural integrity?
5
votes
3answers
924 views
How was the Centaur stage fueled in the Space Shuttle?
The Space Shuttle had the ability to launch Centaur booster stages stored inside of the Shuttle during launch. How was this stage fueled, being fueled with cryogenic fuels?
3
votes
1answer
430 views
Could oxyhydrogen (2:1 H2/O2 mix) be used as a rocket fuel
I have been wondering about why oxyhydrogen (HHO) (a ~2:1 H2/O2 stoichiometric mixture) hasn't been used as a fuel? I know it has been used for bottle rockets and other types of small scale rockets, ...
5
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0answers
207 views
Which chemical propellant combination has the highest theoretical isp?
That is disregarding practical factors like making a bomb rather than a rocket in the case of using acetylene+ozone.
I know that the highest isp achieved was 542 with lithium, hydrogen, and fluorine. ...
1
vote
2answers
268 views
Is there a chemical propellant combination with Isp between Methalox and Hydrolox?
Methalox rocket engines (Liquid Methane and Liquid Oxygen) have theoretical specific impulse in the high 300's.
Hydrolox rocket engines (Liquid Hydrogen and Liquid Oxygen) have theoretical specific ...
4
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3answers
1k views
Why is space fuel cheap compared to rocket cost?
I have been pondering on this question for some time now. I've searched the web and realized that fuel for Falcon 9 (SpaceX) costs around 200 000 dollars per launch, while the launch itself costs 62 ...
3
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2answers
195 views
What are the choice of materials for LOx pumps casing and impellers?
Given the highly corrosive nature of LOx and the extremely low temperature, what materials are usually used for the LOx pumps?
Steel, Copper, and many alloy tend to be flammable in liquid Oxygen ...
4
votes
1answer
671 views
How much did the fuel for the space shuttle missions cost?
I'm looking for a rough estimate on how much it costs. I understand that it is a propellant mix, and that NASA contracts a company to produce it, but I am yet to come across a figure per kg of the ...
3
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0answers
108 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 ...
