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Questions tagged [fuel]

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

4
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3answers
178 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 ...
8
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2answers
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 ...
13
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1answer
1k 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 ...
4
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1answer
1k 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 ...
8
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2answers
2k views

Where is the Lithium-Fluorine-Hydrogen tripropellant currently?

One of notes near the end of "Ignition!" included: Using lithium and fluorine alone (no hydrogen) their maximum specific impulse was 458 seconds. But when they proportioned the lithium and ...
7
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2answers
510 views

Which heavenly bodies have stuff to make rocket fuel?

Which planets or large moons of our solar system are currently known to have the raw materials needed for us to produce rocket fuel? Mars, for example, has plentiful CO₂, and we know how to produce ...
7
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2answers
2k 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 ...
1
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1answer
79 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 ...
1
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0answers
34 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 ...
7
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0answers
262 views

Why is SpaceX's Raptor's design so simple in comparison to SSME?

What is especially striking to me is how simple Raptor is in configuration compared to SSME. The Raptor doesn't have an LP fuel or oxygen pump. What's even more surprising, if we are to compare the ...
4
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1answer
204 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?
6
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1answer
208 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 ...
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3answers
3k views

Do rockets deplete the oxygen on earth?

When we use our rockets in space, are we using up a fraction of the finite oxygen here on earth? I'm assuming that it's a negligible amount at our current rate of space travel, but could this ...
4
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1answer
169 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 ...
11
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1answer
617 views

What is the ortho/para issue with LH2 as a fuel?

I remember reading somewhere that a catalyst was used to change the ratio of ortho- vs para-hydrogen before it is loaded as LH2 propellant on a rocket. What is this exactly, and why is it necessary? ...
3
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1answer
96 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 ...
5
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2answers
300 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 ...
3
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2answers
419 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 ...
4
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2answers
997 views

Why does Juno use “mixed oxides of nitrogen” oxidizer for propulsion? Which ones?

In the recent Spaceflight 101 article Rocket Burn postponed for NASA’s Juno, to remain in elongated Jupiter Orbit until December it says: Juno uses a bi-propellant main propulsion system with ...
6
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3answers
5k views

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?
8
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3answers
390 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. ...
12
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2answers
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? ...
2
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1answer
77 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 ...
13
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5answers
4k views

Can a rocket motor be shut off after ignition?

After ignition, if any problems occur such as fuel leakage, can a rocket motor can be shut off?
2
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2answers
137 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 ...
4
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1answer
86 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 ...
5
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0answers
71 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 ...
21
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7answers
4k 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 ...
18
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3answers
3k views

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 ...
0
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1answer
118 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 ...
9
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1answer
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?
0
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1answer
85 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 ...
14
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3answers
4k views

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. ...
2
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1answer
49 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 ...
3
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1answer
197 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?
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2answers
407 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 ...
20
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3answers
4k views

Reasons why liquid anhydrous ammonia fuel chosen for the X-15? Has it been used in other rocket engines?

Both Flight 90 and Flight 91 of the North American X-15 crossed the Kármán line, reaching altitudes of 106.01 and 107.96 km respectively. Both flights were piloted by Joseph A. Walker, who became in ...
4
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1answer
102 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?
12
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2answers
1k views

What is this red gas at the exhaust of the Long March 3B rocket during liftoff?

While watching today's live stream of the launch of the China National Space Administration (CNSA) Long March 3B rocket carrying Chang'e 3 lunar exploration probe and the Yutu rover to the Moon, @...
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1answer
58 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 ...
0
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3answers
8k views

What is the formula to calculate how much fuel is needed for a rocket?

I'm theoretically trying to launch a rocket for a school project and therefore I chose Saturn V. I took its weight of 140.000kg (308 647 pounds) and I'm trying to calculate how much fuel it'd take to ...
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2answers
517 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 ...
5
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1answer
151 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
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1answer
76 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.
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0answers
82 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 ...
2
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1answer
102 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 ...
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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 ...
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0answers
202 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?
6
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1answer
175 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 ...
12
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1answer
558 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 ...