Questions tagged [engines]
Questions regarding equipment used to propel a spacecraft or a rocket. Questions about attitude control jets should be tagged "attitude".
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Under which conditions we can we safely operate an UNDEREXPANDED nozzle? [closed]
Are there any dangers in using an underexpanded nozzle? Or some kind of losses?
Thank you
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Rocket Engine Failure Rate
I am a reciprocating engine machinist and understand that rocket engines are much much more complex. But I am curious why they have such a high failure rate. Even modern rockets are designed to ...
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How do ablatively cooled rocket engines compare to regeneratively cooled ones, in terms of mass?
Assuming equivalent thrust and single continuous burn duration, is there a figure that roughly tells the difference in mass between these two engines cooling methods? This question focuses on first ...
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How do Centrifugal Turbopumps work? How do you make one?
I recently visited Wikipedia to look at centrifugal pumps and axial pumps. Centrifugal pumps are very interesting, and I was wondering how they work in more depth. I really don't understand how they ...
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ROFI Temperature
Since hydrogen-fueled rockets usually require Radial Outward Firing Igniters (ROFI), what is the temperature of the sparks from this system? When seen at RS-25/RS-68 ignition, they don't melt but ...
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How common have the various orbital launchers' rocket engines been?
A fleeting thought on my sentiments about the disposability of RS-25s (rare! Only 47 made before the RS-25E/F contracts? Few remain! Complain about them being expended for SLS!) versus Raptors (one ...
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Do smaller engines have a higher thrust to weight ratio?
For a given chamber pressure and shape,
thrust is proportional to nozzle area, which is proportional to the square of dimensions
mass is proportional to the volume, which is proportional to the cube ...
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Can rocket engines produce high voltages?
I was reading Michael Collins' account of the Apollo 11 TLI burn [1], and I wonder wheter the "flashes", "lightning", "sparks flying" and "insistent fireflies" ...
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Do full flow rocket engines still use injectors? If so, how? How exactly are the oxidizer and fuel sent into the combustion chamber?
I'm learning about rocket engines and full flow engines, and I'm a little confused about what goes on in the combustion chamber. It was my understanding that injectors were pretty much necessary to ...
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Air-Augmentation on a VTO&L super heavy lift
I'm working on a basic design for an Air-Augmented first stage, which boosts the second, expendable, stage from a near-orbit, to allow for deorbit of the second stage.
Essentially it's an SSTO that ...
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Has the ISP been published for NASAs new rotating detonation engine demonstrator?
Nasa just announced successful testing of their new rotating detonation engine:
https://www.nasa.gov/centers/marshall/feature/nasa-validates-revolutionary-propulsion-design-for-deep-space-missions
I ...
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What would be the most fuel-efficient propulsion solution to accelerate a 100-ton piece of NEO asteroid towards Earth?
We need acceleration to about 300-500 m/s relative to an NEO asteroid - to get to an LEO.
What is needed is the lightest package possible, that includes engine, fuel tanks, control module and ...
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Lorentz force space propulsion
While browsing for Space propulsion, I've found the following article
As shown in Figure 2, the conductor I0 gets through the coil L0, and they are fixed together and form a system. a is the main ...
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What is SpaceX doing differently with Starship to avoid it exploding like the N1?
Both Starship and the N1 have more than 30 rocket engines. The N1 exploded after having a chain reaction from a failed engine.
N1 rocket engines:
Starship’s rocket engines:
Unlike the N1, SpaceX has ...
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What is a bimodal or multimodal space rocket engine? Especially a nuclear-powered one?
I can't seem to find a specific answer anywhere....
I wonder if it means using the radioactive fuel to power the electronic equipment, purely via natural decay, but also using the same fuel to power a ...
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What is the cause of soot in the plume of the Raptor engine?
Though the Raptor engine burns quite clean, it was clear from some early test flights that it did produce some visible soot:
There have been differing explanations for the exact cause of/source of ...
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What engine cycle is best for a large lunar lander?
I'm specifically looking for an answer to whether a pressure fed or pump fed engine would be more feasible considering a mass of over 50T(metric, of course), and a single stage to descend and then re-...
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Is an open expander cycle rocket engine driven by a gasified oxygen turbine technically feasible?
Is an open expander (bleed-off) cycle engine that uses the gasified cryogenic oxidizer instead of the gasified fuel to drive the turbo pumps technically feasible?
I was thinking of a first stage open ...
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Thrust & acceleration produced by a rocket engine
For given propellants, with their mass flow decided by the rpm of the turbo pump, what decides the thrust and acceleration produced by a rocket engine? Can we control them independently?
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What is the most promising fusion technology for rocket propulsion?
Given current fusion technology (barely above q=1 as of the 12/12/22), is a fusion plasma torch rocket engine viable?
I'm asking in terms of basic science, not engineering, as I know this would ...
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Whats the exit pressure of the F-1 engine?
I cant find anything online, does anyone know what it is?
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Proton rocket's engine fizzle
Why does one of Proton's engines sometimes leave a dark gas?
Is it some sort of byproduct of the UDMH and NTO reaction or did the engine fail?
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What is the difference between a spin up test and a spin prime test?
What is the difference between a spin up test and a spin prime test? And if there is no difference, why not just use the first of those two terms, it being more descriptive?
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How to test vaccum engines at sea level? [duplicate]
SpaceX is testing its Raptor vacuum engine (RVAC) at sea level (without any facility that can simulate near vacuum conditions). How can they do this without flow separation happening?
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What is the propellant tank weight or weight ratio on dry weight of liquid propellant rocket engine?
I need propellant tank ( or oxidizer tank)'s dry weight- without propellant and engine mass. For example ARES-V's dry mass at earth departure stage is 21,795 kg, What percent of this is tanks' dry ...
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What am I missing about rocket nozzle isentropic flow?
Playing a bit with Cpropep-Web, something looked wrong to me about how it models isentropic flow through a CD nozzle.
I'm taking the RS-25 characteristics as an example. I ask for a frozen equilibrium ...
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What engine cycle does the RS-88 and its hypergol derivative use?
A comment on this question Orange lines coming from rocket engine nozzle? stated in part
The RS-88 is not a full flow engine and there is not a visible bypass exhaust. ... Perhaps they eject the ...
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Orange lines coming from rocket engine nozzle?
This image of a test-fire of the RS-88 ethanol/LOX engine from Wikipedia. It is apparent that there are these orange lines extending from inside the nozzle into the plume. What is it, and why is this ...
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What are better ways to deliver heat directly to propellant in a Thermal Rocket design for use in launch than UV such as in the Nuclear Lightbulb?
Most advanced, high-power engine concepts that I came across aren’t suited for atmospheric launch, so I got curious about what kinds of engines could launch a very heavy craft from the surface of a ...
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What is the area of the SSME nozzle knowing only thrust at sea level and in vacuum?
Looking at the SSME Wikipedia RS-25 Space Shuttle Engines, the data shown that the thrust at sea level ($F_{sl}$) is 1.816*10$^6$ N, while the thrust in vacuum ($F_{vac}$) is 2.278*10$^6$ N. Knowing ...
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Which orbital class rocket has highest TWR at liftoff?
Which orbital class rocket (active or retired) has the highest thrust to weight ratio at liftoff?
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How Spacex's Raptor Rocket Engine starts?
How does the Spacex Raptor rocket engine start? What are the different stages of startup?
Is the propellant pressure in the tanks sufficient to drive the turbopumps and ignite the preburners and then ...
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What is the exhaust temperature of a liquid oxygen + liquid hydrogen vacuum engine?
Ideally the exhaust of stochiometric liquid oxygen + liquid hydrogen rocket would be fast moving chunks of ice at zero kelvin. In this way all the potential chemical energy in the fuel/oxidizer is ...
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Why aren't Dual Engine Centaurs used anymore?
The last DEC flew in 2004 (excluding Starliner) on an Atlas II. Why aren't they used today for commercial payloads (again, barring Starliner)? I understand that DEC is more expensive than SEC as it ...
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What rockets use a methalox propellant?
I’ve found that the SpaceX Raptor rocket engine and the BE-4 rocket engine use methalox (Liquid Methane and Liquid Oxygen), is there any other rocket engines that use a methalox.
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What are these things on SLS' engine mount?
Watching the scrubbed inaugural launch of SLS, there has been plenty of close up views from the vehicle, including a close up of the SSME engine mount, that exhibits those white extruded squares or ...
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What is the maximum weight a raptor 2 engine can lift up at sea level on earth?
Regardless of target orbit, how can I calculate the maximum weight one engine can lift?
If the raptor's TWR is 140 and its Thrust is 1.81 MN then:
W = F / TWR = 12,900 N ==> m = W / g = 1.3 tons
...
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How is the stainless-steel tubing in rocket engines brought into the correct shape?
Some American rocket engines have TCA's (thrust chamber assemblies) built after a certain scheme:
A combustion chamber, including part of the nozzle, made of several dozens of stainless steel tubes ...
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Why was the V-2 engine so successful?
The engine which powered the A-4/V-2 was brought back to the US as part of (I believe) Operation Paperclip, along with a couple of affiliated Nazis. The USSR effected a similar result with Operation ...
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What is a rocket engine spin up test?
Recently I came across internet about SpaceX's Booster 7 explosion in a ball of fire during an engine spin up test. I searched Google about rocket engine spin up test but I got no hit. What is a ...
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Matching reference thrust to engine given certain parameters
I am running a simulation where a reference thrust value is meant to be matched by a liquid engine which I know the following information about:
$"F_{vac}=100000"$ N, $I_{sp}=364$ sec, $D_e=1.01$ m, $...
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Is there an ultimate break-even point with rocket nozzle length or expansion ratio in a vacuum?
I know that in an atmosphere, you don't want your expansion ratio to be too high, or it will cause some big problems, and that vacuum engines are restricted by the space they have to fit in, but if we ...
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Why would you want a low turbine temperature in an expander bleed cycle engine?
In a paper by Sippel et al. [1] the following statement is made on page 2: "Consequently the LE-5B turbine drive gas
temperature has been successfully reduced [w.r.t. the LE-5A engine]."
...
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What is the largest number of rocket engines ever successfully used on a single craft as of 2022?
A fully stacked Starship was rolled to the pad this week for testing. The byline caught my eye, though (emphasis mine)
SpaceX moves a massive rocket with 33 engines to its launch pad for tests
No ...
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Are nozzle plugs taken out before launch or are they ejected upon ignition?
Inspired by this question. For most orbital launch vehicles, do their engines have nozzle plugs installed and what happen to them at launch? Are they manually removed during the prelaunch/rollout or ...
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What's this inside the RD-0120?
There is a decent shot of the RD-0120's inside in this video:
I guess it's something covering the injector plate or even the combustion chamber since the SSME's injector looks very differently:
Also,...
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What is the purpose of the shrouds surrounding these rocket engines?
While researching the purpose of some rocket engine components, I came across several images of perforated shrouds surrounding the combustion chambers of rocket engines.
I was highly curious about ...
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Where is the gas generator on the RS-68?
Wikipedia notes that the RS-68 uses a gas generator cycle. I've already seen a couple of photos of the RS-68 and I do not see any gas generator exhaust pipe or a pipe leading into the nozzle. So where ...
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What is the point of having a central rocket engine when it receives performance losses?
Recently I asked this question about center engine performance and received an excellent answer from @OrganicMarble. The first sentence of the answer is
If anything, the flow field interactions hurt ...
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What are the negatives associated with Thrust-augmented Nozzles aka Afterburning Rocket Engines?
An interesting comment here introduced me to the concept of Thrust-augmented Nozzles aka Afterburning Rocket Engines. The pubs I've read on it so far introduce the concept as a way to provide good ...
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