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Questions tagged [propulsion]

Systems for propelling a spacecraft from one place to another, such as rockets.

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Converting Discharge Voltage to Temperature? Hall Effect Thruster Calculation

Trying to follow a Hall Effect Thruster design process given in this video: Hall Effect Thruster Design Video In 25:59, there's a calculation in which the presenter takes discharge voltage and ...
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What could be the proprietary propellant blend that “Apollo Fusion” claims to have developed for it's hall effect thrusters?

According to the info posted on the Apollo fusion website http://apollofusion.com/ , they claim to use a propellant blend that offers " 2-3 X more impulse per mass and volume" in comparison towards ...
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1answer
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What's the actual oxidizer/fuel ratio in the combustion chamber of the Vulcain?

I'm working on a simple exercise on the Vulcain, but I'm having a hard time figuring out what the real O/F ratio is, in the combustion chamber. I need the mixture ratio in the chamber to calculate the ...
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1k views

How do you confirm ignition in the combustion chamber of a rocket?

Is ignition confirmed using a temperature sensor, pressure sensor or another device?
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Purging process of a rocket engine

Does spacex purge Falcon 9 engines after landing ? If so, which gas is used for purging?
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1answer
127 views

Insulation used in the plumbing line of the actual rockets

While using the pipes for plumbing of the liquid propellants at pretty low temperature because of which ice form on the line if not insulated or poorly insulated, which can lead to liquid to gas ...
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Effect of the location of igniter in starting liquid rocket engine

What will be the effect of off axis igniter, say a Spark igniter has to be used along with a pintle? Will the igniter being off axis have any effect on engine start? Also, will an off-center igniter ...
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Why is SpaceShipTwo's nozzle scarfed? [duplicate]

As seen in this photo (from here) there appears to be a significant scarf to the nozzle. I'm familiar with scarfing reaction control jet nozzles to fit fuselage contours, but this one is completely ...
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2answers
395 views

From the General Thrust Equation towards Tsiolkovsky, how to explain dropping these terms along the way?

The NASA Glen Research Center tutorial page Rocket Thrust Equation links to the General Thrust Equation page which starts with: Which transcribes into MathJax as: $ \ \ \ F = \dot{m}_\mathrm e ...
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What is the inner wall of the thrust chamber made of?

With advancements in additive manufacturing, the manufacture of regeneratively cooled thrust chambers is simpler nowadays. Brooklyn based startup Launcher Space Inc. says most 3D printed engines use ...
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How to make a orbital launch tube work?

Normal rockets would not work in a pressurized tube, but could a stage be made for the diagonal launch tube to save fuel and weight? Can the bottom stage be nuclear powered? Unlike the piston launch ...
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3answers
2k views

Will an array of multiple ion engines still be more efficient than a single chemical engine?

I was just thinking the other day and got this idea out of my head. I'm not an aerospace expert or anything even close to it, so please understand even if this turns out to be a really basic question: ...
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Is it feasible to take liquid Helium in a Pressure Fed System?

Can liquid Helium be flowed through a heat exhanger to increase its temperature and pressure which will further pressurize fuel-oxidizer tanks.
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4answers
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What is the most energy efficient & inexpensive propulsion system other than chemical fuel oxidizer that could be used in rockets?

I have read ionic/plasma propulsion system don't provide enough thrust to even lift themselves in Earth's atmosphere & photonic beamed propulsion is not in application yet so there any other ...
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1answer
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Are ion/plasma thrusters sufficient for propulsion from Earth? [closed]

I'm looking to make something like a jet pack and I'm looking for super cheap thrusters to carry humans than normal chemical oxidized ones that are used in spacecrafts. I read that ionic thrusters can'...
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How are the combustion chamber length and diameter decided

How are the combustion chamber length and diameter decided? Are there any proper formulations or procedures?
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1answer
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Density of propylene when used as rocket fuel, and advantages (if any) over RP-1?

Recently Vector space from USA has said that propylene is a better choice of fuel than RP-1. See Ars Technica's After a decade of testing, propylene rocket fuel may be ready for prime time Why is ...
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Externaly delivered non-nuclear pulse propulsion?

This question asks about the feasibility of an Orion-like pulse propulsion system using chemical explosives instead of nuclear explosives as pulse unit. Unfortunately, those simply lack the energy ...
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Could electric fans lift a rocket strait up like a multi propeller drone? [closed]

Could electric fans like the ones below lift a rocket? What is the amount of electricity needed to lift a interplanetary rocket? Could a nuclear power plant provide enough electricity? https://en....
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When regenerative cooling is used, how is the nonuniform radius of the combustion chamber handled?

As the combustion chamber necks down and flares out, the 1-D cross section past which which fuel must pass as it cools the wall of the chamber will change. If there are lots of tubes, they will bunch ...
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How is supersonic rocket exhaust able to match sea-level pressures?

I understand that the diverging portion of a rocket nozzle speeds up the flow and also expands it, in order to best match ambient pressure outside. However, doesn't higher speed flow lower the ...
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2answers
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Which propelling device would be the most efficient for a space elevator?

There are many types of propulsion from electric turbine engines to steam powered catapults once used on aircraft carriers. Which of the many types of propulsion would be the most efficient in getting ...
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Why is using a space elevator cheaper than rocket power?

Why is rocket power so much less efficient? In both cases you want to lift a given weight a certain height. What does climbing a tether give you that you don't have when using rockets? Wouldn't a ...
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Is there an absolute limit to single stage ∆V when tank mass is a fixed faction of propellant mass?

Many space exploration fans are familiar with the rocket equation [https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation] $$\Delta V = V_{e} \times ln\frac{M_0}{M_F}$$ where $V_e$ is the exhaust ...
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Could a laser ablation-based propulsion system really accelerate an object to 0.001 c?

Comments below this answer suggests that a laser ablation-based propulsion system, where the laser is separate from the object to be accelerated, could accelerate an object to about 1/1000 of the ...
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Hows does “Glenn Research Center's sapphire refractive secondary concentrator” work?

Clicking through NASA.spinoff.gov I came to the page for spinnoff 2001 Glenn Research Center and found this: Glenn Research Center's sapphire refractive secondary concentrator will be used with ...
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Would a flat superconductor create surface area to increase its diamagnetic field uni or bilaterally to propel in space? [closed]

Instead of using a standard solar sail material could the sail be built of diamagnetic material and sail faster? Is there a way to make a thin flat sail that both uses the dimagnetic properties of a ...
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3answers
187 views

At what size does a bigger solar sail stop increasing your acceleration?

Is there a point where the larger solar sail would not add more thrust? What is the most thrust a solar sail can produce? Can a solar sail be added to an ion engine and work better?
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1answer
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Which of the orientation is preferred for static fire testing of a liquid rocket engine - vertical or horizontal?

Liquid rocket engine's hot fire testings are performed both vertically and horizontally. Vertical orientation - Falcon heavy, Falcon 9, Rutherford engine, UCSD Engine test from 2014 , Merlin 1D, ...
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Is there a use case describing the need to perform xenon propellant offloading?

I can understand hydrazine offloading and the hazards associated, but I'm wondering if there is such a need for xenon offloading.
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1answer
226 views

Which is the preferred mode of liquid rocket engine cutoff - fuel lean cutoff or fuel rich cutoff?

When a bi-propellant liquid rocket engine receives a command to shut down, will the fuel gets cut off first and then the oxidiser - a fuel lean cutoff? Will the oxidiser gets cut off first and then ...
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Transportation on the Mars I Air

Due to the thin atmosphere generating lift on Mars is difficult at a lower speed, Flying is hard until aircraft go supersonic and then it becomes difficult to control(Ref.). The landing would not be ...
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Optimal Thruster Layout For Cubesat

I am working on a simulation of a Cubesat for rendezvous. Using the Clohessy-Wiltshire equations I calculate delta-v. Now that I know the thrust needed for operation, I would like to know how to ...
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268 views

Is this description of the “dipole drive” and how it would work physically correct?

Comments in chat have noted the recent post in the Centauri Dreams blog titled The Dipole Drive: A New Concept for Space Propulsion. In contrast to the single positively charged screen employed by ...
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143 views

What kind of security while using solid propellent? [closed]

I'am going to to make a propulsion test with sugar and $\mathrm{KNO}_3$ (with large quantities). What should I wear before to protect myself?
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1answer
169 views

Could a spacecraft be propelled by the deflection of a very high number of charged particles?

I am wondering if a spacecraft could be propelled through interplanetary space via the deflection and/or displacement of a very high number of charged particles contained within the Sun's solar wind. ...
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STS: How much thrust did the nominal post-MECO LOX dump produce?

Following up to some questions asked in comments to the answer to this question: With pressure-fed engines, is any measurable thrust generated by venting the pressurant out the engine bell after ...
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1answer
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Could the interaction of the Sun’s solar wind and trapped plasma ions be used to propel a rocket through interplanetary space?

I have recently had a renewed interest in comets and how comet tails are formed. From studying this process, a thought occurred to me that perhaps plasma ions can be created within a long hollow ...
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thrusters, force torque, distribution matrix , orbit maneuver

I have a few questions about computing torques and forces. I use the same configuration as in the thesis titled An Attitude Control Sysytem Design Based on the Turksat-1b Geostationary Satellite. ...
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Why does the Falcon 9 use RP-1/LOx and not LH2/LOx?

Why does SpaceX use RP-1 in the first and second stages of their rockets? In my view at least the second stage could use hydrogen as it currently is not being reused. I am aware that you have higher ...
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1answer
69 views

Rocket engine power vs. Sound

Is there any relationship between the sound emitted from a rocket engine and the amount of thrust it gets at surface temperature and pressure?
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What is the droplet size that is desirable for pintle injectors?

The pintle injectors tend to generate droplets after impingement of the fuel and the oxidiser stream and I understand that the droplets will be premixed. In such a case, even a larger premixed ...
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297 views

Exhaust products of hypergolic propellants

On videos of Soyuz docking to ISS we can see exhaust from the control engines (if background is dark enough). For example here Soyuz TMA-19M docked to ISS at ...
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1answer
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What is the speed that we can reach using tsar bomba as a propellant?

The idea of using an atomic bomb as a propellant was introduced in project orion, but it did not work out because of the interdiction of using the atomic bombs. So I decided to calculate the speed ...
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Potential improvement to BFR or New Glenn if equipped with aerospike exhaust on their engines?

Aerospikes basically tackle the issue of the variability in required expansion ratio for a rocket engine to be efficient at a given altitude. A recent example though mired in legal issues is a small ...
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2answers
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What ion engine is used by Hayabusa2?

Hayabusa2 is on its final approach to asteroid 162173 Ryugu, expected to arrive in July 2018. Like its predecessor, Hayabusa2 uses an ion thruster for deep-space propulsion, but I can't find any ...
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214 views

Can we hit speed of light using Antimatter?

if we use Antimatter as method of propulsion is it possible to reach speed of light ?
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Nozzle material of Apollo Lunar Module ascent engine?

There are some photos of the Apollo Lunar Module ascent engine, see 1, 2, 3. The nozzle looks like being made of epoxy and fiberglass. The fibers are wound in two different directions. Is it true ...
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1answer
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Roughly how long will the SABRE engine need to switch from air-breathing to closed-cycle?

The SABRE engine is designed to be used on a single-stage-to-orbit type of spaceplane. What sort of delay might occur between shutting down the air-breathing operation and switching to a closed-cycle ...
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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?