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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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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 ...
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2answers
206 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 ...
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1answer
725 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 ...
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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 ...
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1answer
382 views

Why spray LOx into combustion chamber, if GOx is more effective?

Are there any issues in transforming the liquid oxygen into gaseous oxygen before injecting into the combustion chamber? Gaseous Oxygen will be readily available for combustion and will mix well with ...
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2answers
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How do rockets keep their fuel in a liquid state?

What are some of the measures engineers would take to ensure that the LOX and other similar fuels are kept below their boiling point during flight?
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2answers
226 views

Using asteroids as propellent source

if we could capture an asteroid or meteor, can we use it as a vehicle for space travel? From what I understand, propulsion is a result of mass flow, so we could use a rail gun configuration to propel ...
7
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1answer
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Could the SpaceX Falcon 9 Block 5 work without sub-cooling the propellants?

I've been reading about some concerns about the densified (sub-cooled) propellants for Falcon 9 crewed missions in Spaceflight Now's article Lawmakers question safety, schedule for Boeing/SpaceX ...
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1answer
286 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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1answer
292 views

Why did the “Secretive SpaceX Zuma Launch” make a big “S” or yin-yang shape in the sky?

The Space.com article Strange Sky Spiral May Come from Secretive SpaceX Zuma Launch shows images from this Tweet and this tweet, the second of which was posted by Dr Marco Langbroek (@Marco_Langbroek):...
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What do rockets eject?

So for instance, for the space shuttle,liquid hydrogen will react with liquid oxygen to produce water vapour. Is only water vapour ejected from the rocket? Or will the ejected mass be a mix of water ...
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Efficiency of 3 in line boosters of a shuttle? [closed]

What is the most efficient scenario for a total of 700 Newtons of thrust on three lined up boosters? If the air pressure for the payload booster isn't the same, can they make an efficient air ...
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3answers
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What fuel is used in the second stage of orbital launch vehicles?

What types of propellant are used in the second stage of multi-stage rockets? For example, the Falcon 9. Is it the same combination as the first stage? I've found plenty of information about the first ...
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1answer
444 views

How much CO2 would city-to-city rocket flight produce compared to airliners?

After seeing Elon Musk's proposal of using rockets to travel from city to city I was wondering how much fuel such a rocket would use, and how would that compare to traditional flights in terms of ...
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2answers
604 views

Longest continuous burning chemical rocket engine?

I'm curious as to what rocket engine in a launched rocket burned the longest in a continuous fashion. I'm not interested in testing burns or inter-planetary engines which are designed for low-thrust ...
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1answer
1k views

Red oxygen as solid oxidizer?

Would it make sense to use solid (aka red) oxygen as oxidizer instead of liquid oxygen? (Red oxygen: An allotrope of solid oxygen (O8))
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1answer
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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 ...
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1answer
379 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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4answers
238 views

How to gain speed in space?

New concept: What about if we are to depend from external forces? So we cannot produce any kind of propulsion from our ship. Previous question: I know that there are two main ways to gain speed in ...
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1answer
267 views

Manufacturing H2 and O2 rocket fuel components?

I'm curious as to the typical manufacturing (or gathering) methodology of H2 and O2 used in modern rockets for fuel and oxidizer. It would seem that the most straightforward process would seem to be ...
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3answers
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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 ...
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1answer
239 views

Nuclear thermal rocket working fluid performance

After reading an announcement about NASA restarting NTR (nuclear thermal rocket) research I was wondering about how a working fluid would be chosen. For clarity, the working fluid is the gas that is ...
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2answers
413 views

How would E85 work as rocket fuel?

In the question Can I make my own RP1? the comments talk about using ethanol and water as rocket fuel. That made me wonder how well easily availible ethanol fuel for cars such as E85 (85% ethanol 15% ...
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1answer
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Can I make my own RP1? [closed]

Is it possible for me to buy kerosene from a local store and then try to refine it to the extent where it would be considered RP1. If so how would I do it? For those who are wondering me and a group ...
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2answers
347 views

In what state are the propellants entering a (RP-1) rocket engine's combustion chamber?

What I mean is that, when the fuel and oxidiser are mixed, at what state (solid - liquid - gaseous) is the oxygen and the fuel. To be more precise, I would like to know how it is for the Merlin engine ...
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3answers
517 views

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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1answer
180 views

Could a Stirling engine be used to pump propellants into engines?

A stirling engine is a type of engine which converts thermal energy into mechanical energy. An example of a rather large one is shown here I know this is pretty much the same principle that an ...
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1answer
6k views

Do booster stages run out of fuel, or are they purposefully shut off?

When an expendable booster rocket stage nears the end of its burn, does the guidance computer shut the engine(s) off at a certain velocity/altitude for the mission, or does the stage completely ...
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0answers
375 views

Could Sodium metal be used in rocket fuel?

For instance, I read that the Hercules X-265 rocket motor used in the Sprint missile was a solid double base propellant that used nitrocellulose with zirconium metal staples and nitroglycerin as a ...
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1answer
597 views

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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0answers
449 views

How much fuel is necessary for 2nd stage of Falcon 9 rocket to land?

What is the fuel mass nedeed for the 2nd stage of Falcon 9 rocket to land, how much compared with its total fuel mass that it has? Or how much delta-v is necessary? Would it be able for Falcon 9 to ...
2
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1answer
515 views

How much fuel is needed for the motor landing and taking off on mars?

For example, the Apollo lunar module landing on the moon was worth approximately 60% fuel of the total weight (on wiki 8 tons of the 15 tons). Departure from the surface was about 50% of fuel (2.5 ...
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1answer
410 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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Why don't rockets use propane?

Most BBQs use propane. Propane burns quite well and it is quite clean. So why hasn't anyone use it as a rocket fuel??
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1answer
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How to find the optimum balance between amount of fuel and number of engines?

I'm coming from a background of Kerbal Space Program, so I'm not 100% sure all of this applies to real-life but I'm asking in the hopes someone might tell me that. Yes, I know, it's not real space ...
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0answers
86 views

Hypergolic slugs with gaseous reactants

Based on points raised in this question about hypergolic slugs. My understanding of a hypergolic slug is that it is a solid or a liquid on a paper patch placed in the combustion chamber and it will ...
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1answer
391 views

Could super-cold LOX be used in every rocket engine?

Super-cold LOX gives advantages in performance for a rocket. But it isn't used in all rockets. SpaceX's Merlin 1D rocket engine uses super-cold LOX. Also NK-33 use sub-cooled LOX. Could super-cold LOX ...
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2answers
620 views

What's the specific impulse of a human farts/urination?

I was curious about how effective farting/urination would be as a propulsion system, but I couldn't find any data on the specific impulse of human farts/urination. Could you actually get a couple of ...
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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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2answers
395 views

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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1answer
620 views

Odor of a rocket launch?

Thinking of the primary propellants used for typical rocket launches (such as Hydrogen, RP-1, solid fuel), what are the odors of the exhaust and burned fuel components? I'd think that the Hydrogen ...
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2answers
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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 ...
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1answer
75 views

What is $C_p$ in the fuel efficiency equation?

On page 94 of Ignition! an equation for "Frozen equilibrium calculation": $$ c = \left[ 2H/M \right]^{1/2} \left[ 1- \left( {P_e \over P_c} \right) ^{R/C_p} \right]^{1/2} $$ All quantities are ...
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1answer
682 views

How large a percentage of its fuel did the Space Shuttle use to get to orbit?

What percent of the total available fuel onboard the space shuttle, external tank, and rocket boosters was required to launch and get the space shuttle into orbit? Or phrased another way, what percent ...
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5answers
941 views

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
859 views

How much fuel is being consumed by all spacecrafts in orbit?

It is possible to supply spacecrafts in orbit in cis-Lunar space with oxygen from fuel production facilities on the Moon or on asteroids. What is the size of this potential in-space oxygen market ...
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2answers
211 views

Chemical Fuel Improvements

With advances in chemical engineering, could chemical propulsion have a fuel (or fuels) that would allow it to compete with newer, more advanced form of propulsion (such as electrical or nuclear) or ...
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3answers
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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 ...
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1answer
911 views

What was the result of the propellant predictions in the last chapter of “Ignition!”?

In John D. Clarke's Ignition! (1972), the author spends the last chapter making predictions about the future of liquid rocket propellants. I thought these were very interesting, but I realize the book ...
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2answers
303 views

Space Shuttle fuel

As I know, Space Shuttle used the same amount of fuel for every mission. And used OMS for finishing orbit. Then how it is possible that, for example STS-1 which hadn't payload and was in roughly 266km*...