Questions tagged [liquid-fuel]

Questions regarding rocket propellant in liquid form, the main type used for chemical rockets.

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2
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1answer
388 views

ULA's plan for LH2/LOX 2nd stage that can maintain propellant for an extended period of time?

Business Insider's (long) article SpaceX's biggest rival has a 'genius' plan to cut its rocket launch costs more than 70% contains the statements sourced from ULA's CEO Tory Bruno: Vulcan should ...
9
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1answer
5k views

Rocket Engine Plumbing: Still don't understand the Full Flow Staged Combustion Cycle

I just found this incredible video KSP Doesn't Teach: Rocket Engine Plumbing and ran through it a few times. It's very helpful in the way it outlines the various issues first, and then designs the ...
10
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3answers
2k views

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 "...
6
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2answers
3k views

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 ...
5
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2answers
2k views

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 ...
15
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3answers
4k views

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?

After having read this answer I wondered what happens if hydrazine freezes. It looks like it is "normal" and not like water, in the sense that it contracts when freezing, unlike water which expands ...
6
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2answers
2k views

Structural composition of shuttle liquid fuel tank wall

Somewhere I read the shuttle fuel tank kept structural integrity only thanks to internal pressure of the fuel, a'la inflated balloon; empty it would collapse under own weight; and the walls were ...
5
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2answers
307 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 ...
4
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1answer
2k views

How to seal the connection between the combustion chamber and outer shell in this rocket engine model?

Here is rocket engine drawing. The combustion chamber made from copper and the outer shell from stainless steel. The coolant, either water or gasoline will be between With either pressurised water or ...
4
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1answer
261 views

How often can liquid hydrogen engines be restarted?

A proposal for lunar development, LunarCOTS, relies on a reusable shuttle running on LH2 and LOX to work. It lands, is refueled on the lunar surface, and then takes off again. Presumably it could sit ...
2
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1answer
789 views

Problems with the “How to Design, Build and Test Small Liquid-Fuel Rocket Engines” text

For those that have read or consulted the text: How to Design, Build and Test Small Liquid-Fuel Rocket Engines (Rocketlab/China Lake). Otherwise, see steps 10-13 here: https://risacher.org/rocket/...
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3answers
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How was fuel crossfeed achieved, between the main tank and the Shuttle?

Whenever a fan of Kerbal Space Program mentions the super-efficient 'asparagus staging' in any professional context, the automatic response is 'That won't work. KSP fuel pipes are pure magic.' The ...
11
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1answer
275 views

Liquids Plumbing on board

When a cargo mission is flown toward the ISS, there are at least four different kinds of liquids that may need to be moved into/out of the station: Propellant for Zvezda's thrusters Water Wastewater ...
0
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2answers
699 views

What are these thirteen purple grape-like things inside this tank?

I am not sure this is a view of the inside of a liquid propellant tank, and even if was, not sure if it belongs to a Falcon 9 per se. But there are places for fourteen round objects at the far end, ...
11
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2answers
2k views

Why does the BE-4 use methane as fuel?

I understand the Mars ISRU reasoning for SpaceX's Raptor which is also going to be methalox based. But why would ULA, who is the prime customer for BE-4 besides Blue Origin itself, chose to support a ...
8
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1answer
1k views

Can we use liquid propellants in amateur rockets?

Is it possible and worth it to use liquid propellants like liquid oxygen and liquid hydrogen in amateur rockets? What are the other types of liquid fuel used? Moderator's Note: Remember discussion ...
17
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1answer
785 views

What was the reason to use different fuel for the Apollo Service Module propulsion system and reaction control system?

The Apollo Lunar Module LM used the same fuel/oxidizer combination (Aerozine 50 fuel / nitrogen tetroxide (N2O4) oxidizer) for both descent and ascent stage engines and reaction control system. This ...
15
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5answers
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If LOX/LH2 were used in a fuel cell powering an ion engine could it provide a greater delta-v than with a conventional engine?

Question: If LOX/LH2 were used in a fuel cell powering an ion engine could it provide a greater delta-v than with a conventional engine? Conditions: Start in space in a stable heliocentric orbit (no ...
14
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4answers
2k views

Can a solid first stage compete with a liquid fueled first stage?

The thing about solids is that they can have awe inspiring amounts of thrust compared to liquid engines, as you can see in this collection of boosters and thrust levels: Shuttle SRB - 2.8 Mlbs Ariane ...
8
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3answers
966 views

Are ICBMs and orbital launchers similar enough to be co-developed today?

Russia has two types of hypergolic liquid fuel ICBMs deployed, UR-100N and R-36M2 Vojewoda and they are working on the big Sarmat. There's in this category also the Chinese DF-A5. (A list of ICBMs ...
24
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1answer
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How did sloshing prevent the Apollo Service Module from moving safely away from the Command Module and how was this fixed?

The Insider.com article 'We could have lost the Apollo 11 crew:' A once-classified anomaly nearly killed NASA's first moon astronauts, a new book reveals describes a problem during reentry of several ...
14
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1answer
995 views

What is the advantage of using Helium over Nitrogen when used for pressurising LOx?

In this Twitter post of the plumbing line diagram(left half) by LauncherSpace, one can notice that Helium is used for pressurising LOx while Nitrogen is used for pressurising Kerosene. Why the ...
7
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2answers
502 views

What challenges are there for more, smaller liquid fuel engines instead of one large?

Some questions popped up about difficulties of creating throttleable liquid fuel engines. I wonder why the obvious alternative isn't more common: multiple engines, from which only some will be lit; ...
7
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3answers
777 views

Why doesn't Rocket Lab use a solid stage?

I was just reading about the Scout, an all-solid rocket, and thought of Rocket Lab's Electron, which seems to have a similar mission of deploying small payloads to orbit. I understand the engines to ...
5
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1answer
215 views

How will Robotic Refueling Mission-3's liquid methane tank remain full for six months without any boil off?

Space.com's Lasers, Crystals and 36,000 Worms Will Ride a SpaceX Dragon to Space Station says: To fly on those journeys, astronauts might have to someday harvest fuel from the surface of the moon ...
5
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1answer
373 views

Is a fluorine/hydrogen engine feasible for use in space? [duplicate]

Fluorine is a bit more efficient chemically than oxygen. It has never been used as a launcher oxidizer because it and its exhaust products are so toxic. That's as much I've heard about it anyway. But, ...
5
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1answer
135 views

Why can’t cryogenic propellants be storable, at least on the ground, via refrigeration?

Cryogenic fuels (liquid hydrogen, liquid methane)1 and oxidisers (liquid oxygen)2 are the rocket propellants of choice where raw performance is the overriding concern, due to the very high performance ...
4
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1answer
305 views

Liquid Helium (4.2K) sealed, then raised to sub-LOX temperature (~70K) - what is the new pressure?

In this question there is discussion of the large differences in temperature between liquid helium-4, subcooled liquid oxygen (sub-LOX) and cold kerosene (RP-1). Approximate temperatures are 4.2K, ~...
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1answer
1k views

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
120 views

How much fuel/oxidizer was held in the piping of the Shuttle orbiter?

The space shuttle main engines were in the orbiter portion of the vehicle, but fed fuel (LH2) and oxidizer (LOX) from the external tank. Suppose the external tank is ejected before the LH2 and LOX ...
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0answers
68 views

How to overcome the challenge of igniting kerosene using spark plugs?

Discussions in this question and its answer, concerning the use of spark plug ignition for Kero/GOx system outlines the energy limitations of spark plugs to ignite the mixture. But Ignition Transient ...
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2answers
422 views

Is nitrous oxide hypergolic with anything reasonably safe and obtainable?

Can I start an amateur rocket using nitrous oxide as either oxidizer or monopropellant, using a hypergolic slug of something reasonable for use by an amateur rocketeer? What substance could it be?
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0answers
105 views

How are the liquid propellant umbilical cord protected from the exhaust?

The launch pad umbilical cords supply propellant to the rocket, and will definitely have some remaining at the time of liftoff. I remember the Saturn V footage wherein a heavy protection door slams ...