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Questions tagged [propulsion]

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

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1answer
158 views

Efficiency of a nuclear thermal rocket

I am trying to calculate the specific impulse and thrust of a nuclear thermal engine, given the thermal power of the reactor, the maximum working temperature and the propellant. I'm calculating the ...
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2answers
1k views

Could a cubesat propel itself to Mars?

I wrote the answer below to the question Could a cubesat be propelled to the moon? before realizing that it said Moon and I'd written it for Mars, so I've cloned that question and moved the answer ...
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Could a cubesat be self propelled to the moon from LEO?

Is it possible with current technologies to propel a cubesat, which is launched from Earth, to the moon? If current propulsion systems are able to do so, how do I continue the research in this topic ...
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86 views

What kind of “jet engine-like propulsion” does HyperSciences use to accelerate projectiles to sub-orbital altitudes?

The Teslarati article For HyperSciences, geothermal energy builds a path to space describes the use of technology which has been applied to drilling to launching projectiles to sub-orbital altitudes ...
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How do you determine what the temperature will be in the combustion chamber of a rocket engine?

I am guessing it is dependent on the fuel and oxidiser and the chamber pressure but is there an equation that would calculate the chamber temperature?
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1answer
40 views

Weight Flow Rate

I read in the book INTRODUCTION TO ROCKET SCIENCE AND ENGINEERING by T.S.T that Rocket Engineers design how big the throat of the nozzle should be based on the Weight Flow Rate. So my question is HOW?
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What could go wrong if someone overpowered an ion engine?

The X-3 ion engine is the most powerful ion engine ever made, and puts out an astounding 5.4 N of force, using 103 kW. It's fuel is inert xenon gas, ionized and heated to a plasma. Now, what would ...
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1answer
151 views

What type of propellant does Spacex plan to use in Starship for long duration missions?

For long duration missions such as ones to mars what type of propellant would be best suited?
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1answer
76 views

What happens when LOX and H2 are injected into the combustion chamber of a rocket?

I can't seem to find an answer on this. I thought that when oxygen and hydrogen get injected they collide and break bonds etc. to form water vapour which because of the pressure in the combustion ...
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How to calculate the force drop due to multiple thrusters firing?

When multiple thrusters are connected to one pressurized propellant tank and multiple thrusters are fired simultaneously, this will cause a pressure drop in the supplying pipes and as such a drop in ...
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84 views

Very Low Gravity Bicycle

There are a couple of existing questions about riding bicycles off of Earth. Designing a bicycle for Mars? Can you ride a bicycle on Deimos? Bicycles are lightweight and proved a reliable method ...
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1answer
143 views

Advantage of full-flow staged combustion vs conventional staged combustion engine

Referring to the question in this thread. What is the advantage of full-flow staged combustion (FFSC) vs conventional staged combustion rocket engine? In FFSC we feed the full volume of fuel and ...
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1answer
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Why does the pressure & temperature ratio in a diverging nozzle continue decreasing once it hits supersonic flow?

From Sutton chapter 3 he uses this figure to describe the ratios of pressure//area//temperature as functions of Mach Number. I know that we are bringing the fluid to an adiabatic "stop" through ...
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2answers
152 views

Is presssuized gas absent in a turbopump-driven rocket engines?

For RL-10 rocket engines, are the propellent pumps able to provide the propellent without a source of pressurant gas?
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1answer
131 views

What methods are proposed for storing cryogenic fuels (esp. hydrogen) in space for months or years?

Current Launch vehicles and upper stages must only keep their fuels for minutes or hours, so they are only insulated to keep boiloff to a few % per day - I've seen 21% per day quoted for Centaur on ...
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1answer
152 views

Is it possible to protect a Cubesat's electronics from 100g of acceleration?

I am currently researching the feasibility of setting up a coilgun that launches Cubesats for a paper. 1 cubesat per launch total payload mass <100kg.
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1answer
136 views

Could protons in the Sun's solar wind be used to create a photonic laser thruster for a spacecraft?

I have a conceptual idea for a photonic laser thruster for a spacecraft and I am wondering if this particular idea has already been thought of and whether or not it is capable of generating enough ...
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3answers
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If specific impulse is directly related to exhaust velocity, would a ion post-accelerator improve the Isp of a propulsion system?

I understand that ion- and hall thrusters resemble a particle accelerator, and that led me to wonder if a post-accelerator (particle accelerator) used to boost the velocity of the ions would improve ...
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1answer
132 views

Could a spacecraft be propelled by a 180 degree deflection of two charged particle beams?

I am wondering if the electrostatic deflection of two charged particle beams could create enough thrust, via the Lorentz Force, to propel a spacecraft. Please reference the picture below. This ...
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Could a Soyuz-MS deorbit after a failure of its deorbit engine?

The scenario: A Soyuz-MS spacecraft is on-orbit and ready for its deorbit burn. The crew then discover that there is a fault in the propulsion system and the deorbit engine can't fire. The craft is ...
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1answer
87 views

Can I able to use RP 1 and LOX in metal tin small size rockets? Is that possible? [closed]

I love rockets. Planning to build a tin rocket but not with water and air pressure. I would like to build a small metal tin rocket using fuel as RP 1 and oxidizer as LOX. I know this is too hazardous ...
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2answers
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Calculating thrust pressure from ion thruster for rocket thrust equation

So recently i have been very interested in the possibilities of using ion thrusters as power interstellar propulsion units, however when it comes to calculating ISP it have absolutely zero idea how ...
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2answers
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What are some notable cold gas thruster propellants, and why?

Cold gas thrusters are a very simple and reliable form of thruster that operate only by spraying a compressed gas, without any chemical reaction. What are the most common, performant, or otherwise ...
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How much delta-v is lost to heat of exhaust?

It occurred to me that all of the kinetic energy not going exactly in the opposite direction of a spacecraft is wasted! Since heat is essentially kinetic "noise" in objects, I wondered how much more ...
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1answer
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Why did the MarCO space probes use fire extinguishant as their propellant?

In many news articles, it's mentioned that the MarCO spacecraft, launched with InSight, used fire extinguishant as the propellant for its cold gas thrusters. I originally assumed that this was ...
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2answers
88 views

Propellants used for different Mars landers [till 2018]

What propellants have been used by lander to land on Mars surface?
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158 views

How much thrust can plasma produced from water have?

If water could be converted to plasma for a propellant by electricity how much thrust would water produce? What would be the byproduct?
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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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1answer
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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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2answers
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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
152 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
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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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1answer
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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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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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56 views

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
325 views

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
124 views

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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1answer
284 views

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
290 views

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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349 views

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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1answer
168 views

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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0answers
73 views

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
249 views

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 ...