Questions tagged [fuel]

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

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26
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4answers
4k views

Does the NK-33 engine require subcooled kerosene so cold that it turns to wax?

It was mentioned in this answer and in several other places on the internet that the kerosene fuel used by NK-33 engines needed to be subcooled enough so that it reached the same density as the LOX, ...
9
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1answer
693 views

How do rocket propellant combinations rank in terms of “brightness”?

While a booster on the shuttle had a bit more than twice the thrust of the shuttles engines at take-off, I'd venture a guess that it produced on the order of a thousand time more visible light. In ...
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3answers
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Why would oxygen be stored as a super critical fluid?

Organic Marble just answered a question about Apollo 13 in terms of the storage of Oxygen, and posted some fascinating stuff, including the fact that Oxygen was stored as a super-critical fluid. I ...
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1answer
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How would the Saturn V have differed if the first stage was also LH2/LOX?

Since both Kerosene (RP-1) and liquid hydrogen (LH2) continue to be important liquid fuels used with liquid oxygen (LOX), something can be learned by comparing how they are used. This is covered well ...
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3answers
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Why are hydrogen-fluorine fuels not used for rockets more frequently?

Many rockets use hydrogen- and oxygen-based propellants as fuel. Why are hydrogen-fluorine fuels not used? It has a specific impulse of 390 seconds, higher than hydrogen-oxygen combustion (360 ...
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What are the phases of ignition (and flameout) of a liquid fuel engine?

As I observed ignition of several rocket engines (Shuttle, AMDE, Lynx Suborbital, Saturn V) they all come through a couple phases - emitting various vapors, unfocused flame, etc, before the proper "...
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1answer
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Vector-R's LP-1 and -2 engines use liquid propylene as fuel with LOX, advantages and distinctions from kerosene or propane?

@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 ...
19
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Could I home-brew my own rocket fuel?

RP-1 is highly refined kerosene. If I bought a supply of commercial-grade kerosene, by what process could I convert it to RP-1, And, while I'm at it, do I have any good choices for non-cryogenic ...
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Could 3D printing be used to achieve perfect grain geometry of solid and hybrid rocket motors?

Solid cores, either for solid-fueled of hybrid rocket motors, use various propellant grain geometries to achieve thrust curve needed. For example, some of these could look like:    &...
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Is the pressurization of propellant tanks necessary for structural integrity?

Propellant tank pressurization is a critical aspect of liquid propellant rocket design. Many designs use high pressure helium, heated and recirculated, however the propellant gases themselves can be ...
7
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Pros and Cons of LH2/LOX vs Other Fuels

As I stated in the answer to another question, LH2 suffers some serious drawbacks compared to other fuels. Off the top of my head, they are Extremely low density, resulting in: Lower mass-fraction ...
16
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1answer
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Does the Soyuz spacecraft chemically stabilize its 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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Why is there a hole in solid rocket engines?

I would like to find out why there is a straight hole down the middle in all solid rocket engine motors. I thought it only makes sense in hybrid engines where pure oxygen needs to be blown down the ...
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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 do the exhaust flames from cryogenic stage engines appear to be separated from the nozzle?

Why do the exhaust flames from cryogenic stage engines appear to be separated from the nozzle?
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Why is TEA-TEB chemical ignition used instead of spark ignition?

Both the Saturn V and the Falcon 9 use TEA-TEB to ignite their kerosene-fueled engines. TEA-TEB is pyrophoric, igniting spontaneously on contact with air. This poses handling issues; it must be stored ...
16
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2answers
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How was reserve fuel calculated for the Apollo missions?

A quick follow-up to How much fuel was used for a Space Shuttle launch? My memory is a little foggy; I seem to recall reading the Apollo 11 mission commander depleted his reserve fuel landing Eagle. ...
12
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1answer
455 views

Why is one of these two concurrent fuel-dump spirals blue?

This comment mentions the amazing double-spiral event seen in the night sky from Norway that Wikipedia calls the 2009 Norwegian spiral anomaly. The Gizmodo article Giant Mysterious Spiral Takes Over ...
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Is atmospheric skimming for propellant feasible?

A recent comment in a discussion of satellite refueling mentioned the possiblity of a spacecraft dipping into the atmosphere from LEO to obtain oxygen. Similarly, the science fiction RPG Traveller ...
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1answer
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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?
12
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1answer
688 views

Flying fuel tanks! Which deep-space spacecraft had the largest fuel mass fraction?

The Los Angeles Times' Deborah Netburn just wrote a really nice retrospective; ‘OK. Let’s do it!’ An oral history of how NASA’s Cassini mission to Saturn came to be with plenty of photos and quotes ...
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1answer
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Would (theoretically) metastable solid metallic hydrogen even need an oxidizer?

In this answer there is discussion of some research on the potential, future use of a solid metallic hydrogen phase that would be metastable at ambient pressure as a rocket propellant. The work is ...
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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 ...
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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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Why did it take so long for methane to be used as a rocket propellant?

SpaceX have put methane on the map as a rocket fuel, but they weren't the first to consider its use. The first experiments in building a rocket engine that uses methane date back to 2007. Now methane ...
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How does the launch risk posed by plutonium compare to the launch risk posed by propellants?

For outer solar system exploration, virtually the only feasible power subsystem are Radioisotope thermoelectric generators (RTGs). These include plutonium, which may carry considerable risks (see ...
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1answer
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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 + ...
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1answer
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How does an Electric Solid Propellant rocket work?

I saw the section in Wikipedia about Electric Solid propellants but I can't figure out what it really is, and how it works. It sounds like a solid propellant rocket that you can start and stop ...
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How are fuel tanks filled with cryogenic hydrogen?

Cryogenic hydrogen can react with the atmospheric Oxygen to produce an explosion: as well as being cold enough to liquefy (and possibly solidify) atmospheric oxygen, which can be an explosion ...
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Is the EU really banning “toxic propellants” in 2020? How is that going to work?

This comment links to an archived presentation by Tesseract "The space transportation company offering revolutionary propulsion" says on slide 8: Timing is right Small satellite ...
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2answers
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Has (theoretically) metastable metallic hydrogen been considered for use as a propellant?

I'll just point to the following two questions and their associated answers for background: For the recently reported production (January 2017) of metallic hydrogen in the laboratory - what is the ...
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How are cryogenic rocket propellants delivered to the launch pad?

I work at a university that gets LN2/LHe (liquid nitrogen and helium) delivered a couple times a week by a large tanker truck outside my office. It seems to work well enough to deliver a couple tons ...
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1answer
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Changes made to ISRO GSLV-D5's CUS and FBTP since GSLV-D3's LH2/LOX CUS failure to sustain ignition?

The launch of the ISRO GSLV-D5 launching India's GSAT 14 advanced communications satellite (weighing 1,980 kg) is slated for 19th of August, 2013, flying in the GSLV Mk.2 configuration with an Indian-...
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In a cryogenic fuel rocket, at what pressure is the fuel injected into the engine?

The pressure in the Space Shuttle's main engines must be very high to get the vehicle off the ground (with the SRB assist, of course). With such high pressures inside the engine, how do you inject ...
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Is the supercooled LOX used in Falcon 9 Full Thrust a first?

One of the changes made to the Falcon 9 v1.1 Full Thrust was using supercooled liquid oxygen at 66 K (-340 F) as well as chilled RP-1. I've seen various claims that this is a first in the industry. ...
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Xenon vs Hydrazine, “Should I Stay or Should I go?” Dawn mission decisions

edit 2: There seems to have been some announcement/extension by NASA (20-Oct-2017), possibly this will shed more light on the issues in this question. edit 1: Several months have passed since this ...
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Overcoming pressure differential to feed fuel into rocket engines

When pumping fuel and oxidizer into a rocket engine, I presume the pump must create more pressure than the inside of the combustion chamber, otherwise the liquid would back-flow. Is this right? Then ...
6
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1answer
331 views

Could oxygen be used in a resistojet in a vacuum environment?

Resistojets heat a compressed gas or vaporize a liquid to expand it through a nozzle for thrust. They improve a bit on the performance of cold gas thrusters. This experimental water resistojet managed ...
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Why use Kerosene?

According to SpaceX's website, the Falcon 9 uses kerosene as fuel. According to Wikipedia, diesel fuel beats kerosene in energy density in terms mass by 2.8 MJ/Kg and in volume by 5.6MJ/L, so why ...
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1answer
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Are MMH and UDMH interchangeable?

Can Monomethylhydrazine and Unsymmetrical dimethylhydrazine be used one in place of another for the class of the existing orbital maneuver engines (with reduced performance may be)? Such as Shuttle's ...
14
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1answer
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How long is it feasible to store cryogenic fuels?

Working with liquid nitrogen all day, I am constantly bothered by their boiling away, forcing me to go get more from the storage dewar. Likewise should be the case with any cryogen, e.g. LH2 and LOX ...
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Use of carbon monoxide as propellant on Mars

Is it possible to use carbon monoxide as propellant for a rocket? For example, carbon dioxide from the atmosphere of Mars could be transformed to carbon monoxide and oxygen via photochemical ...
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Are oxidizer to fuel mixture ratios based on mass or volume?

Wikipedia references the ratio of liquid oxygen to RP-1 as 2.56. Is this based on mass or volume? Are they using some typical combustion chamber pressure?
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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 ...
14
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1answer
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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 ...
13
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1answer
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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 ...
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1answer
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What is the spherical tank in this drawing of the BFS?

The big news in this article is the extremely large carbon-fiber fuel tank. However, the drawing in the article does not show it well. Instead what stands out like a sore thumb in the drawing is the ...
3
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1answer
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Why would it be “less bad” for hydroxylammonium nitrate monopropellant to freeze than for hydrazine?

Answers to Is it bad if hydrazine freezes on a spacecraft? Is it always kept as liquid, or can it be safely allowed to freeze and then thawed when needed? explain that while the freezing of hydrazine ...
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1answer
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Is there a derivative of LMP-103S, called LMP-103, that has even higher performance?

I found this PDF while searching for any and all info related to LMP-103S, which you can read more about in my related question. In the PDF, if you scroll down to page 4, you will find a chart ...
14
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1answer
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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 ...