Questions tagged [thrust]
Force produced by pushing against a reaction mass in space à la Newton's third law: "For every action there is an equal and opposite reaction." The thrust of a rocket engine is the forward force produced by expelling the exhaust mass (reaction mass) in the backwards direction.
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Falcon 9 Merlin 1d thrust calculated through every moment of flight
I am currently trying to recreate the launch of falcon 9 in unity. For the calculations I need the thrust of the first stage (only doing it for one stage for now).
How to calculate it depending on the ...
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How are rockets gimballed to produce a gravity turn for the space shuttle?
I'm trying to simulate a gravity turn using a gimbaled thruster. I'm using the dynamical system described in a previous post of mine to execute a gravity turn by changing the angle $\phi_T$ between ...
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Are side boosters sometimes angled even if they are symmetrically arranged?
When more than one side booster is added to a first stage to increase thrust and they are distributed uniformly around the core (as opposed to those shown in links below) thrust does not seem to need ...
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What does it mean when the Voyagers "switch thrusters"?
The Gizmodo article NASA fights to keep the Voyager probes running after four decades says:
As another example of the probes' need to adapt to circumstances to keep going, Voyager 2 has fired up ...
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Why is there a hole in solid rocket engines?
I would like to find out why there is a straight hole down the middle in all solid rocket engine motors.
I thought it only makes sense in hybrid engines where pure oxygen needs to be blown down the ...
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Upper stage structural loads on ascent?
In another question, this came up:
For example, if a Falcon 9 launches 20 tons of fuel to dock in LEO, how can the same upper stage be used to launch 40 tons of fuel to the same orbit? Doesn't it ...
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Shear forces between Shuttle, tank, and boosters - what pushes what?
This is the question that I should have asked here. The space shuttle and the two solid rocket boosters (SRBs) are mechanically attached to the giant tank.
SRB's, shuttle, and tank all experience ...
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What is a non-propulsive vent?
I just hear the term "non-propulsive vent". Is it a thing, a vent that does not cause propulsion?
Or is it an event, where a vent of some unwanted gas has occurred which did not result in a ...
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How should mass specific impulse calculated for relativistic exhaust?
This answer says:
Optimising for Isp only is problematic, as it's simply:
$$I_{sp} = \frac{v_e}{g}$$
Which is the same as optimising for exhaust velocity.
With no constraints on thrust, particle ...
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Has an object ever been put in orbit where the first stage was always at maximum thrust?
Variable thrust through changing the number of engines burning, or through propellant throttling, or other means is often/usually done to reduce maximum aerodynamic stresses on the rocket as well as ...
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Why do pressure-fed systems have to be pressurized with helium or nitrogen?
This is something I just don't understand. The way I see it, propellant can be pressurized all on its own in the tank. Just pump a lot of the stuff in there and make sure the tank is strong enough. ...
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How did the Space Shuttle maintain thrust/weight balance
As a seasoned KSP player, I am aware of how important it is during ascent to have center of thrust and center of mass perfectly aligned. If you don't, your rocket will deviate from its course and ...
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How far would the STS get without the SRBs
This is a very stupid hypothetical - sorry!
Would the Space Shuttle Orbiter plus external tank have been able to leave the pad just using the SSMEs (i.e. without the solid rocket boosters ~80% of its ...
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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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Ways to obtain thrust curves of different grain geometries
Different grain geometries in solid-fuel rockets produce various thrust curves:
I can imagine it's not too difficult to obtain a thrust curve of a specific grain geometry with a measurement while ...
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Relationship between part dimensions and performance of ion electrospray thruster
I got the relationship between power, thrust and specific impulse for an ion electrospray thruster as follows:
$$P/T= 1/2 \times g_o \times I_{\mathrm{sp}}$$
Where: $P$ = power required (in Watts), $...
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What are the various ways that rockets measure the instantaneous thrust of each engine?
@DavidHammen's answer to Engine failure: how to detect? mentions thruster sensors.
This intrigued me and so I thought I'd ask about how this is done.
Thrust is a critical parameter to know in real ...
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How much of the exhaust speed is due to combustion and how much is due to the injection?
The thrust $F$ of a rocket engine is given by
$$F=\dot{m}v$$
where $\dot{m}$ is the mass flow and $v$ is the exhaust speed.
Now the first factor, $\dot{m}$, is almost entirely due to the turbo pumps (...
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Microwave drive for cubesats
Theory: how is this?
I was doing a lot of research about the EmDrive thruster, i find 50% papers says that it work and other 50% saying that the "thrust" is a product of the interaction with ...
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How did NASA calculate 22 million "rocket horsepower" for the SLS Booster?
This answer to Does NASA really report the power of rockets in horsepower? cites NASA news item Space Launch System Booster Aimed and Ready to Fire which says
"What's impressive about this test is ...
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Could New Horizons' thrusters' ISP be as low as 157 sec?
A discussion below How much of a deep space spacecraft's structural mass is useless dead weight after launch? Any plans to shed it in the future? has lead to https://nssdc.gsfc.nasa.gov/nmc/...
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Using a reverse sling + compression sock to give an asteroid an initial boost - possible?
building my a related question, I have a hypothesis in question:
Assuming that we can get a tug spacecraft near an asteroid worth mining, at appropriate but faster speeds can we use a slingshot with a ...
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Are there any other examples of right-angle exhaust diverters in spacecraft?
The Scott Manley video The Only Pilot to Shoot Down A Spacecraft - A Space Ace talks about the ASM-135 ASAT and its successful test launched from an F-15.
He shows images from the page The F-15 ASAT ...
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Why does the Indian PSLV rocket have tiny boosters?
I have noticed that the Indian rocket PSLV has tiny strap-on boosters attached to it on the sides at the bottom. Why would these be used instead of just using a larger first stage? Why is there an ...
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Why do nuclear rockets (e.g. NERVA) have such poor Thrust-to-Weight ratios?
Nuclear fission releases far more energy per kilogram of fuel than conventional hydrocarbon sources. However, proposed nuclear rocket engines like NERVA (https://en.wikipedia.org/wiki/NERVA), while ...
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Where does the thrust act in a rocket engine and how is it transferred to rocket structure?
A rocket engine is basically a device that generates a high pressure inside the chamber and the pressure difference creates a force.
A nozzle helps in effectively accelerating the flow and increases ...
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Do the propellants ionize in chemical rockets?
When combustion takes place in a chemical rocket (LOX/LH2), do the gases ionize due to high temperatures? If they do, how do they get around the problem?
Ionization is a waste of energy I believe, ...
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why do under-expanded engines have less than ideal thrust?
I've been looking into rocket propulsion a bit and got stumped on something. I read that the thrust generated by an engine can be determined by the following:
$$
F = \frac{w}{g}v_{e}+A_{e}(P_{e}-P_{a})...
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Why do chemical rockets encompass a weird shape on this thrust vs. Isp graph?
Consider this graph of engine thrust versus specific impulse (from https://dawn.jpl.nasa.gov/mission/ion_prop.html):
Most propulsion technologies encompass roughly rectangular regions on the graph. ...
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Can we thrust a rocket from earth using electric power?
I wanted to know if we can thrust a rocket from earth using electric power? If yes, how and has anyone tried to do that?
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What is the lowest first stage thrust for a launch reaching orbit?
What is the lowest thrust for a first stage rocket for a rocket that reached Earth orbit?
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Can you reach the Sun by only thrusting horizontally?
Suppose you have a hypothetical spacecraft launched from Earth.
When it escapes from Earth's gravity it will still be orbiting the sun at roughly the same velocity as the earth, approximately 30km/...
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Optimal thrust vs isp for variable isp rockets (VASIMR) when taking off/orbiting
This question was initially inspired through playing Kerbal Space Program, however I am seeking a more general answer.
I've been playing the excellent Near Future Propulsion mod for KSP, using ...
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With pressure-fed engines, is any measurable thrust generated by venting the pressurant out the engine bell after flameout?
A pressure-fed rocket engine supplies fuel and oxidiser to the combustion chamber by pressurising the fuel and oxidiser tanks with an inert gas (typically helium or nitrogen). Presumably, when a ...
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How powerful do cold gas thrusters normally get?
Modern rockets like the Falcon 9 use cold gas thrusters for steering on landing approach when the engines are dead.
Cold gas thrusters are common in smaller satellites and spacecraft, which way a ...
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Some exercise questions about Tsiolkovsky's Rocket Equation and Thrust Equation
I have found 6 of the question's answers, but I don't know they are correct. The last question about time of the burn I get negative result -0.42 seconds. Time could not be a negative value, so I ...
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How much thrust to launch a regulation size FIFA soccerball into orbit
How much thrust is necessary to launch a regulation size FIFA soccer ball into orbit around the Earth? Let us assume a size 5 which weighs between 420g and 450g. Remember, we will need thrust to ...
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Why is a 1.5:1 TWR desirable for a reusable launcher?
According to a Teslerati article linked from another QA:
The most critical component for the booster, according to Musk, is that there is “a lot of force pushing up.” He states that to launch ...
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What is the order of magnitude forces due to Earth's magnetic field, sunlight, drag, oblateness and tidal forces compare?
What in order of magnitude does pressures vary in LEO due to diamagnetic repulsion of Earth's magnetic field, sunlight, drag, oblateness and tidal forces compare on an ideal satellite?
Is there any ...
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Can pyroxene and other silicon compounds be used as a theoretical spacecraft fuel?
I have been reading this patent, which led me to this paper.
The first uses polysilane, which basically replaces the $\text{C}$ in a $\text{-R-C-R-}$ group, making an $\text{-R-Si-R-}$ group. I also ...
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What is the maximum thrust of the Starlink satellites?
As in the title, what is the maximum thrust (in N) that the satellites of the Starlink constellation can achieve? I read that they use Hall-effect thrusters, but I couldn't find a specification of the ...
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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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How and who calculated the thrust required from first stage of launch vehicle Saturn V for moon landing?
Given the lack of clarity about weight of CM, SM and LEM while designing Saturn V, how and who calculated the thrust required from first stage of launch vehicle (Saturn V), for moon landing? were the ...
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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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Is it possible to throttle down the thrust in a rocket engine to 1% just like in KSP?
With any normal liquid fuelled rocket engine it is possible to throttle the thrust up and down, but in Kerbal space program it is possible to bring it all the way down to around a percent thrust. Is ...
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Was the Titan SRM thrust vs time curve engineered to allow for acceleration switches to initiate staging sequence events?
This answer describes the timing between the Titan III Stage 0 (SRM's) and Stage 1 events.
The Titan first stage ignited just prior to SRM separation:
Titan Stage I ignition occurs at approximately ...
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