Questions tagged [propulsion]
Systems for propelling a spacecraft from one place to another, such as rockets.
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What is the load path for thrust in a rocket engine?
This may be a duplicate of this question but I wasn't sure if I could hijack that one to clarify or regenerate interest there.
What is the distribution of axial force in a combustion chamber? My ...
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1answer
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How does lox-lead startup prevent hard start
In my experience with hybrid rockets, the igniter is always triggered prior to or concurrent with ox flow into the chamber (that already has fuel, hopefully lit). This is to prevent igniting a chamber ...
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1answer
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Continuous staging? [closed]
In industrial chemistry it's well known (Armagnac vs. Cognac) that continuous processes are more efficient than batch processes.
In-game microtransactions have competed so favorably with just ...
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Help on Rocket Injector Equation
Hello can someone explain me how can I get the value of (6340) because when I try to solve the given values on the book I get (6423.980075) when I round it off it is still not the right answer can ...
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Ascent propulsion system [duplicate]
For lunar module and spacecraft ascent bipropellant hypergolic fuels comprising of N2O4 oxidizer and Hydrazine derivates/blends are used. How on Earth have we accepted such a dangerous, toxic, ...
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What is the precision attitude estimation strategy for satellites, under impulsive thrust manoeuvres?
Satellites mostly rely on star trackers and gyros for precision attitude knowledge. Under impulsive thrust manoeuvres, I expect the star trackers to blur and provide no attitude knowledge. What is the ...
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1answer
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I need a guidance about reading Rocket Propulsion Elements
I'm 1st grade physics student. I have learnt about units, vectors, kinetics, kinematics, Newton's laws of motion, galileo frames of references: galilean transformation, conservation of energy, ...
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1answer
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Could you carry around with you a rocket pack to get off Mimas?
This question was inspired by the one here:
Is there a self-rounding celestial body from which an Olympian could jump into space?
regarding the, apparently shown infeasible, idea of jumping off what ...
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1answer
178 views
Is the Helical Engine EM-Drive a real aproach to spacecraft propulsion?
I read that the first test was a failure but another theory says that could be done but it may violate the laws of physics. Is this engine a near future possible propulsion system or is just theory ...
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1answer
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Thrust in Newtons to specific impulse
I'm almost certainly missing something here so I'd be grateful if someone could explain but how do I convert thrust in newtons to specific impulse?
thanks.
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1answer
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Help on Nozzle Throat Area Calculation
This is the equation of the nozzle throat area
This equation is based from a book called HOW to DESIGN, BUILD and TEST SMALL LIQUID-FUEL ROCKET ENGINES
This is the solution
The problem is I don’t ...
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1answer
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How was the S-IVB stage configured for the post-extraction retrograde dump?
When answering How exactly did the separation between Saturn V stage 3 and the Command / Lunar Module work? I first wrote that the retrograde dump after LM extraction happened "through the engine".
...
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Do colloid thrusters generate thrust by using only droplets or pure ions as well? If they only use droplets, how are they the same as electrospray?
In all of the research literature I have read so far, I've seen colloid thrusters explained as devices that gain thrust by releasing only charged droplets from ionic liquids as the exhaust mass. ...
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1answer
193 views
Can jet engines be used to launch a rocket?
Following up on my previous question Can a VASIMR Plasma engine be used to launch a rocket?, I was told that VASIMR plasma thrusters are inefficient in an atmosphere. I then had the idea of using jet ...
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Can a VASIMR Plasma engine be used to launch a rocket?
When I was in primary school, I spent countless hours designing spaceships that probably wouldn’t work. It’s only now that I’ve stumbled across some of the old drawings and actually thought if it ...
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When did ion propulsion first see some serious development efforts?
In the video below at about 01:35 Dr. Marc D. Rayman, Chief Propulsion Engineer, NASA JPL mentions that the first time he had heard about ion propulsion was on the ...
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1answer
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VASIMR - Propellant usage data?
So I am using the VASIMR data of approximately 5N of force per 250kw of power draw. As far as I can see, this scales fairly linearly, so 500kw would result in 10N of force. (Might require two engines, ...
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Looking for fuel mass per kg payload data for Ion drives
I'm looking for some information on what the fuel/propellant mass per kg of payload is for ion drives. Hall X3 or VASIMR or whichever is currently the 'best' that we have available.
This isn't for ...
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2answers
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Looking for figures for contemporary interstellar engine options
So I have already done... a lot of reading on this subject lately. A lot. You wouldn't believe. My maths is... functional, probably far above 'average', but when it gets into the realms of the 'rocket ...
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How does a Spacecraft change its orbit?
I am a high school student. I saw the latest Indian spacecraft "CHANDRYAANN 2", which was in orbit around the Earth for 14 days.....
I am so curious to know how a spacecraft changes its orbit. I ...
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2answers
376 views
Who built Starlink's electric propulsion systems?
Wondering who actually built the Starlink propulsion systems?
Did SpaceX develop this technology in-house, outsource or acquire a company that had the IP and bring this back in-house?
Very curious ...
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1answer
245 views
Could the helical engine work?
A helical engine is originally described in this NASA Paper;
see also the youtube explanation by Anton Petrov
The problem may be with powering the device. The original paper uses ions in a toroid to ...
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1answer
86 views
Can a Mars orbiter mass only 50 kg?
A press release
by the SatRevolution consortium says that it plans to send cubesats "as small as 50 kg" to Mars
to "conduct a variety of valuable science." So that means orbiting, not just a flyby ...
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136 views
A question about the feasibility of the Casimir propulsion system [closed]
There is a connection between vacuum energy density and the Casimir effect , see :
https://arxiv.org/abs/quant-ph/0204125
Another reference can be found here:
https://aapt.scitation.org/doi/10.1119/...
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Are there any staged combustion cycle rocket engines under 1000 kN? Is it easier to produce larger engines with this type of engine cycle?
I found that most engines developed with staged combustion cycles are inherently quite powerful. Are there any engines which was developed with the staged combustion cycle with a thrust under 1 MN. ...
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Maximum speed of rocket propellant flow?
In reading this question (Limiting factors of liquid rocket engine thrust), it prompts me to ask if there is an upper limit in how fast the propellant/oxidizer can be pumped into a combustion chamber ...
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144 views
What is the formula to calculate thrust needed to launch from the Moon to Mars?
I want to make a rocket that will travel from Earth then fly from the moon then reach Mars Most of the things are done I just need the formula
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1answer
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Does the moons atmosphere have any amount of human-provided xenon?
Xenon is one of the most widely used propellants for ion engines (sic)- and I also just so happened to stumble on a graph that says the moon could feasibly capture xenon into its atmosphere.
Id ...
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2answers
3k views
Could a complex system of reaction wheels be used to propel a spacecraft?
I was think about different ways spacecraft could feasibly move around and I came across Reaction Wheels as a way they can rotate. So I was curious if a complex system of them could be used to propel ...
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1answer
177 views
Magnetic force-driven propulsion system for an interplanetary/interstellar spacecraft
I have come up with a conceptual idea of a magnetic force-driven space propulsion system. What I believe is very unique about this propulsion system concept is that its working principle should not ...
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2answers
103 views
What is the ideal propulsion for an inner solar system spacecraft?
I've seen the X3 ion thruster named as the future for traveling between planets. Would the ideal spacecraft have only one propulsion? Or would it have multiple sources such as hydrazine and solar ...
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2answers
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How is it that “blow-down” propellant storage systems work in micro/ zero-gravity?
A "blowdown" pressure system is something that is extensively utilized on Earth -- with tons of applications ranging from kegs to high-tech hydraulics.
This architecture focuses on adding a ...
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Why don't we use Cavea-B
Raiz Aerospace raised an interesting question during one of his KSP Realism Overhaul play throughs.
If the RCS propellant Cavea-B is better than hydrazine and less toxic why does no one use Cavea-B, ...
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1answer
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VLEO - ion thrust using atmospheric molecules?
For very low Earth orbit satellites such as the SpaceX Starlink, would it be at all feasible to design an ionic thruster that carries no onboard fuel?
Instead it would simply scoop the atoms directly ...
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2answers
136 views
How does a Hall effect ion thruster have a sea-level Isp of 800? Operates at 1 atmosphere?
Astronatix's SPT-100 lists the following:
Stechkin electric rocket engine. Used on Meteor and Gals satellites.
In Production. 1.35 kW Hall thruster.
Thrust variable 2 to 20 kgf.
...
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How does a “hybrid orbital raising system” based on R-4D (N2O4/MMH) + SPT-100 (Hall effect) work exactly? (Intelsat 38 & 39)
Astronatix's Intelsat 39 lists the two engines
SPT-100 Stechkin 1.35 kW Hall thruster.
R-4D Marquardt N2O4/MMH rocket engine. 490 N.
Question: Why is this combination on Intelsat 39 called "hybrid" ...
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Is it possible to get a spacecraft into earth orbit using Linear Eddy Current Braking on an orbital runway?
The "Space Runway"
[I have slightly edited this to clarify some issues that have been raised]
Luke Parrish mentioned an unusual and novel space launch method to me. The idea is to get a spacecraft ...
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1answer
534 views
Sea level static test of an upper stage possible?
As we know that for the upper stages of the rocket, we need high propulsion efficiency thereby high specific impulse. For that we employ a nozzle with higher expansion ratios.
Now, if we conduct the ...
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1answer
228 views
Why is the thrust to weight ratio of ion thrusters so low?
The more power we feed an ion thruster, the more thrust it generates. In theory, if we could give it, let's say 10 gigawatts of power, it could generate pretty high thrust. In the example I calculated ...
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1answer
209 views
In theory, how much thrust could an ion thruster generate?
Ion thrusters require a lot of electrical power, while their thrust is incredibly low. However, the more power is available, the more thrust can be achieved. What would be the theoretical limit to ...
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1answer
230 views
Could a CubeSat be propelled by this low-tech electromagnetic propulsion system?
I have come up with a conceptual idea for a low-tech electromagnetic propulsion system for a CubeSat, and I would like to know if it would create (on a theoretical basis) a net force strong enough to ...
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How do you calculate burns needed to land?
Assume I was landing a rocket and wanted to do calculations on how to correctly land. How do you determine at what time you fire the engine and at what power to successfully land on a predetermined ...
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Exit pressure for Rocket Lab Curie engine
What do you think the exit pressure for rocket lab curie engine could be?and the area ratio as well? its a kickstage engine and it is said that it has about 25lbf thrust.
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1answer
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Exit pressure value for vacuum nozzle [duplicate]
What value of exit pressure should I use in the design equations for a small liquid rocket engine nozzle for 200km-500km operating conditions?
Since using zero as a value is not possible or else ...
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1answer
155 views
Apollo SM RCS specific impulse?
What is the specific impulse of the RCS thrusters on the Apollo Service Module? This document cites 281 seconds for the LM's RCS thrusters, but I cannot find similar specs for the SM.
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1answer
173 views
Under-expanded nozzle at sea level - is it a problem?
I'm designing a solid rocket motor with a fixed pressure in the combustion chamber $p_{cc} = 70~bar$. When it comes to the choice of the right nozzle, I have to consider the proper expansion ratio, in ...
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2answers
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Apollo CSM RCS maximum number of simultaneously active engines?
Reading the RCS subsystem manual, it seems like each RCS quad of the Apollo SM consisted of four hypergolic engines. Am I correct in saying that all four engines of each of the four quads could be ...
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160 views
ECI to LVLH transformation [duplicate]
I am working on a transformation of ECI coordinates to LVLH (Local Vertical Local Horizontal) coordinates in order to calculate satellite maneuvers. Does anybody know how should I approach the problem?...
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1answer
257 views
Why we don't use cyclotron for ion thrusters?
We know that the advantage of thruster is high efficiency and 'everlasting' propulsion. Which It can not provide a sudden huge propulsion during launch like chemical fuel is its biggest problem. I ...
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What if GOCE rolled 90°?
Reading this question: Is GOCE a satellite or aircraft?
I wondered what would happen if GOCE rolled 90° in either direction, so that it's solar panels become parallel to Earth's horizon, and then ...
