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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Why is the gas jet from Falcon 9's cold gas thrusters so clearly visible?
If I open the valve on my nitrogen bottle there is a terrible noise but the gas jet is totally invisible.
On some Falcon 9 launches, the gas jets are very visible both on ground and in the low ...
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Merlin 1D Engine Throttling
How does the SpaceX Merlin engine control the mass flow rate to throttle its thrust?
Do the pintle injectors move?
Does the mass flow rate to the gas generator change?
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Liquid fuel / Oxygen proportions
A question ive been thinking about:
If an engine works of a liquid propellant(Hydrogen in this case) and LOX, is there a specific proportion required for the two chemicals to burn completely? If so ...
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Merlin engine stoichiometry
As evidenced by the bright exhaust plume at launch, the billowing black smoke rolling out of the flame trench during static tests, the wispy grey effluent from the Merlin Vacuum engine, and the layer ...
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Is the behavior of the Bussard ramjet as described in Poul Anderson's novel Tau Zero accurate?
The ramjet in the novel "Tau Zero" required a separate decelerator which, spoilers, breaks, and causes the ship to career endlessly through the universe. Is this accurate from a real-world engineering ...
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How is chamber pressure determined for rocket engines?
I've been looking for this for quite some time now, and I can't find anything other than calculations where they already assume a chamber pressure. So my questions are two:
What are the equations for ...
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How did the Apollo Lunar Module ascent engine prevent gas bubbling through fuel?
As I understand it, in order to keep the lunar module ascent engine simple, instead of fuel and oxidant pumps, tanks of helium at pressure were used. This pressure was used to force the fuel and ...
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Is ISP all there is to engine efficiency?
Most rocket engines have their efficiency measured by the specific impulse of the engine, which is just how fast the exhaust of the engine is going. Is there another measure of efficiency that's ...
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What organizations correspond to the logos on this ORBITEC Vortex engine rocket?
Images are from the 2012 New Atlas article ORBITEC flight tests new vortex liquid fuel rocket engine. One looks a bit like a US military or DoD logo, one perhaps is ATK, but I'm not sure. Is this ...
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How is chamber pressure and temperature determined for cold gas thrusters?
I'm trying to get some theoretical performance numbers for a cold gas thruster using quasi-one-dimensional flow, and I don't know where to start. For combustion engines you would just take a given ...
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How many kilo's of nitrogen does Falcon 9 load for its first stage cold gas thrusters?
Watching the video of the 1 May NROL launch, I was surprised at the frequency and apparent size of the cold gas thruster firings. Does anyone know approximately how many kilograms of N2 are required ...
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What are the sizes and locations of Progress's thrusters?
Supposedly the Progress modules used for ISS reboost, attitude control, and debris avoidance have two large engines and some number of steering jets.
I know Zarya has 24 large and 12 small in ...
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How well can hybrid motors be throttled?
Pretty self explanatory: down to what percentage can hybrid rocket engines be throttled to? And what fuel / oxidiser combinations allow for the greatest throttling?
I'm planning on using hybrids for ...
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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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Could you use Helium as an oxidizer? [closed]
I am trying to create an HRE (Hybrid Rocket Engine) and i am trying to find the best oxidizer. Do any of you have experience with using helium?
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Rocket Engine demonstrator fuel choice [closed]
As rocket Science and Space Exploration is becoming more and more popular, I'm currently running some numbers, whether it would be possible to build a rocket engine for showing at schools or ...
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Deriving specific impulse from exhaust velocities? [duplicate]
I can't remember where I heard it but I thought that dividing the exhaust velocity by the gravitational pull of a body, it is possible to find the specific impulse of the rocket engine. However, what ...
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Were the Space Shuttle's Main Engines ever off while the Solid Rocket Boosters were firing?
I always though the Space Shuttle needed a combination of its solid rocket boosters and its main engines to remain stable while launching. The following diagram found on Wikipedia seems to agree: ...
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Why did STS-32 require 11 major firings of Columbia's maneuvering engines?
I was reading the Mission Safety Evaluation Report for STS-32 and I noticed the following passage:
The STS-32 rendezvous was one of the most complex the Space Shuttle
had ever attempted, ...
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F-1 rocket engine composition
I was wondering if anyone can tell me what the composition of the Saturn V's F-1 engine's nozzles are? I have looked online and they have many different statistics but I cannot find out what they were ...
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What are the differences between the SpaceX Merlin 1D and 1D+ engines?
I am trying to model the Merlin 1D+ using inventor. I was wondering what the major differences between the Merlin 1D and 1D+ were. I find when I search trying to find a 1D+ engine all I come across is ...
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What are the issues and concerns related to turbopump blade cracks and manned spaceflight?
While the WSJ headline sounds ominous: Congressional Investigators Warn of SpaceX Rocket Defects, Quartz's SpaceX needs to redesign its engine to ensure it is safe for human spaceflight seems to be a ...
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How reliable are pressure fed hypergolic engines?
A fair amount of "what-if" discussion surrounds rocket engine failure at critical points in various crewed missions -- lunar ascent and trans-Earth injection on lunar landing missions, ...
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Was a large-nozzle variant of the J-2 ever considered?
The J-2 engine used on the upper stages of the Saturn launchers has a specific impulse in vacuum of 421 seconds. This is substantially lower than that of the smaller RL10, 440-460 seconds depending on ...
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How did the tangential thrusters for the 2014 LDSD test spin-up then spin-down so nicely?
I just watched the NASA JPL video of the 2014 test of the Low-Density Supersonic Decelerator (LDSD).
Tangential thrusters are used to spin up the craft for stability before the main rocket ignites. ...
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How are the Voyagers' thrusters configured in a novel way to minimize accelerations along Earth-spacecraft axis?
I've just read in Eshleman et al 1977 Radio Science Investigations with Voyager that the voyagers have:
...a novel attitude-control thruster configuration that minimizes accelerations along the ...
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Cassini's main engines' burns "can be blow-down or pressurized (with Helium)" - why?
I just read that when Cassini makes it's first close pass of Saturn's F-ring on December 4, it will be the 183rd time the engine fires. I googled Cassini's engine and found this site which has a cool ...
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Why do rocket nozzles flare?
Why do rocket nozzles open wider at the end than, let's say, get narrower?
Let me explain:
A jet engine works by having this amazing thing called a combustion chamber. The combustion chamber ignites ...
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What is this yellow light on the side of the 2nd stage nozzle - Shenzhou-11 launch
According to Wikipedia the single engine on the 2nd stage is a YF-20 series engine.
What is causing the faint yellow light on the side of the nozzle where there is a tube wrapped around it?
above: ...
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With current or near-future Cubesat propulsion technology, largest aphelion achievable?
Propulsion technology for cubesats and nanosatellites is in active development, but there are at least a few based on sound principles that are likely to be tested in the next few years. There are ...
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Limiting factors of liquid rocket engine thrust
What are the limitations for the 1st stage liquid fueled rocket engines that are currently in widespread use, what are the factors that limit their total thrust? Why can't you just inject more and ...
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What is this 'engine plume interaction'?
SpaceX just released this high-speed footage, writing in the comments:
Missions in order of appearance: May JCSAT-14; July CRS-9 launch, stage separation, engine plume interaction, and re-entry ...
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What is the maximum number of OMS burns executed during a single Shuttle mission?
The recent questions about restarting rocket engines in space made me wonder about this. Every mission used the OMS a couple of times at least but rendezvous missions increased the usage. The record ...
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Have reliable, restartable LH2/LOX engines ever existed? - ever used? [duplicate]
I just wrote the following paragraph as an edit to this answer:
Using LH2 for regular burns to maintain ISS altitude would require a whole new set of engines that may not yet exist anywhere. While ...
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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 ...
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Is there a maximum Isp for "exothermic chemical reaction rockets"?
The question Is there a maximum $\text{I}_{sp}$? reminded me that I once read somewhere that the maximum possible $\text{I}_{sp}$ for a rocket engine based on expansion driven by exothermic, ...
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Which STS mission raised the normal engine throttle above 100%, and what change to the SSME made that possible?
As indirectly stated in an answer to How long does Max-Q last?, during later Space Shuttle launches the main engines were operating at above 100% of their nominal maximum thrust. Specifically from ...
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Does the luminous blue shockwave from the RS-25 engine appear to be rectangular?
Here is a photo of a test firing of the Space Shuttle main RS-25 engine from 1981 from here:
The top of the blue luminous area (a static shock wave?) looks like it has a corner.
Here is a screen ...
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What is the cause of the blue light from LH2/LOX rocket engines?
Below are some screen shots from circa June 2016 launch (or re-launch) videos by Blue Origin (video link) and SpaceX (video link). The New Shepard burns $\text{H}_2$/$\text{O}_2$, while the Falcon 9 ...
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How is engine thrust monitored during flight?
The failure of the Falcon 9 first stage landing during the Eutelsat/ABS mission was attributed to:
thrust was low on 1 of 3 landing engines
which indicate that engine thrusts are part of the ...
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Why can't Pratt & Whitney make RD-180 engines on their own?
From Wikipedia:
Under RD AMROSS, Pratt & Whitney is licensed to produce the RD-180 in the United States. Originally, production of the RD-180 in the US was scheduled to begin in 2008, but this ...
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What are the small gas jets at the rims of the Space Shuttle Main Engines?
As can be seen in close-up footage of SSME ignition, such as the video below,
there are small jets of an unknown gas/vapor emanating from specific points around the ...
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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 ...
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If it is difficult for Merlin engine to have deeper throttling, could it be as an option a different engine at the center of the rocket?
In the landing procedure for the first stage of the Falcon 9 one concern is that :
Merlin 1D throttling at its lowest level still generates more thrust than the empty mass of the first stage. So ...
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What are the maintenance benefits of SABRE engine technology for SSTO launchers?
What are the maintenance benefits of the SABRE engine over all the other engines being considered for the propulsion concepts for SSTO Reusable launchers?
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Are cold gas thrusters viable for model rockets?
Lately I've been exploring the idea of cold gas thrusters, or in this case cold gas rocket engines, to be used in model rockets.
I've read that nitrogen gas can get 73 seconds and helium can get 2.5 ...
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Would reusability affect the performance of a rocket engine compared to a single launch version of that rocket engine
Reusability of the rocket engines, which are the most expensive part of the rocket, is very important to keep low cost of the space rockets and in this way making reality the space programs considered ...
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Has any work been done on alternatives to rolling element bearings in rocket turbopumps?
Specifically:
Using some high pressure gas (before or after combustion) as a fluid bearing.
A superconducting maglev bearing, possibly using fuel as coolant.
Any related work is also welcome.
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How does propellant flow work in a nuclear thermal rocket?
I assume a nuclear thermal rocket with a solid core first. The principle of operation seems simple enough: Bring your propellant close to your nuclear fuel, start a reaction and wait for some heat/...
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Why is there such a long delay in between test firing and launching the SLS engine No. 2059?
I was reading the press release for the recent test firing of the RS-25 engine No. 2059 at Stennis Space Center and I came across the quote:
The next time rocket engine No. 2059 fires for that ...
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