Questions tagged [propulsion]

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Magnetic acceleration for a spacecraft [closed]

This is a naive question about a shower thought, but perhaps someone could indulge me since I don't understand the physics at a sufficient level to know why it would not work. Could the ...
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If the ion trail behind a spacecraft were not neutralized by its electron gun, what would happen?

In the Space Exploration SE question Is there any possible reason to direct the electron gun specifically towards the ion trail behind an ion thruster? there is somewhat of a consensus that there isn'...
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Variable mass, jet airplane thrust

Currently struggling with a momentum problem. I have searched other online answers to similar questions, and the solutions contradict the book answer. Problem: A jet airplane travelling $200\ m/s$ ...
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How does a rocket slow down in space?

I’ve been reading about the conservation of momentum and its applications in deriving the rocket equation. I’m curious whether how can a rocket slow down in space. As far as i can comprehend, a rocket’...
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Lift force on a rocket [closed]

How is the lift force is generated on a rocket? I've tried to find answer online but all efforts were in vain.
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Why aren't rockets launched in movement? [closed]

Rockets launched to reach orbit usually start from a stationary position, engines are started and the rocket slowly gain acceleration upwards, eventually reaching orbit. What I'm thinking is that the ...
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Derivation of Tsiolkovsky rocket equation

My textbook derives the rocket equation from conservation of momentum like so: $$\begin{align}p_i&=p_f \tag{1}\\ mv&={(m-dm_g)}{(v+dv)}+dm_g(v-u)\\ mv&=mv+m\,dv-dm_g\,v-dm_g\,dv+dm_g\,v-...
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What does the Lorentz force depends on? Is it the current or the voltage in case of Magnetohydrodynamic Propulsion?

I recently came across a paper named "Magnetohydrodynamic Propulsion for the Classroom" by Gabriel I. Font and Scott C. Dudley. In that they explain about an experiment in which they try to ...
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Physics of Project Orion

I was reading the book "Project Orion" by George Dyson. For those who are unaware, Project Orion was basically a plan to launch a spaceship by flinging bombs out the rear and detonating them. The ...
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Magnetic ion drive

One of the problems of ion drives is that the electrode is corroded by impacts from the ions we are accelerating. Instead of an electric potential, could we use a magnetic field to accelerate the ions?...
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What causes the pattern around the jet of Soyuz rocket

What physical phenomenon is happening in a following image? Is it dispersion like in prism?Stay Safe.
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What are the theoretical limits of ion propulsion? [closed]

What is the theoretical limit in terms of thrust and energy efficiency a ion thruster can have? Will they ever be able to lift humans on earth? If so, what would the minimum required conditions to do ...
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Travelling in outerspace

Firstly, is it correct that for travel in outer space, the distance that can be travelled with a given amount of fuel is determined by the energy required to overcome the following forces: gravity ...
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Is it in principle possible to store energy more efficiently (per kg) than as antimatter?

I'd like to understand if there's a theoretical bound on how efficiently you could, in principle, store energy to be used for propulsion. The important quantity to consider is energy stored per kg of ...
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Can the Tsiolkovsky rocket equation be translated directly into two dimensions with constant gravity?

By taking the Tsiolkovsky rocket equation $$ \Delta v=v_{\mathrm{e}} \ln \frac{m_{0}}{m_{f}}$$ where $ v_e $ is velocity at which mass is being dispersed, can the same be done with vectors such that $...
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Why are ion-electron collisions important in an ion thruster plasma?

I'm starting to study Ion thrusters, and I was told that for high electron temperature, the collisions between the ions and electrons inside its plasma become important. Why is this like that? I ...
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Confusion about energy conservation

Suppose a rocket at rest turns on its jet and is now moving with kinetic energy $\frac12 mv^2$ in the lab frame. Suppose the efficiency was maximum so that exactly $\frac12mv^2$ of chemical energy was ...
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Maximum Speed for Space Travels

Considering a hypothetical spaceship that has an unlimited amount of fuel, traveling within the solar system planetary plane, what would be considered a safe maximum speed for traveling around ...
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What kind of propulsion would a Scrubbing Bubble use [closed]

The brand name bathroom cleaner Scrubbing Bubbles has a mascot, that is a bubble with a rotating bush on the bottom. Please view this video to see an example of the motion. I would like to know what ...
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Why doesn't NASA try using high-explosives to fuel rockets?

For a smoothly burning liquid-vapor mixture, I understand that burning hydrogen and oxygen is the best possible solution, not just for now but even theoretically. (?) But I read about ideas, that ...
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Method adapted by ISRO

Why does the ISRO change orbits of a satellite in many steps? I've seen them do this in the MANGALYAAN as well as CHANDRAYAAN II missions. From what I understand, changing the orbit of the ...
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speeding up airflow over wings while keeping the propulsive efficiency?

So, let's say we have an aerofoil and we were to apply thrust at where the air speed was the greatest. See figure: Since we apply a thrust to the air it will speed up, thus reducing the pressure even ...
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High frequency ionic wind thruster

I’ve wanted to build an ionic wind thruster for some time now and thought about ways to increase the thrust density. One thing which came to mind is to use high frequency AC tuned in such a way that ...
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On two requirements in order for an equation describing the propulsion of a rocket to hold

A rocket moving with a velocity $v$ releases a mass $\Delta m$ (fuel exhaustion) at a speed $v_{0}$ in a time interval $t$ and $t+\Delta t$, and increases its velocity by $\Delta v$. If we apply ...
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Understanding the interaction between the oar and water

I don't think the propulsion of boats using oars results from the water "pushing" the oars. I understand that momentum is conserved, but in terms of forces, what happens exactly during the interaction ...
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Why can't we fly aeroplane or shuttle directly into the space (beyond 100 km height above Earth's surface)? [duplicate]

Without rockets can we go beyond Karmans line by shuttle or plane?
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Why Don’t We Use Radios for Propulsion?

We’ve all heard the idea of laser propulsion before, but why can’t a high powered RF source be used to propel a body? A simple high current coil with an AC signal applied to it to it could produce ...
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NASA's “Impossible” Space Engine, Take Two [closed]

This question seems to be a close parallel of this one, but it's about a different design by a different author. I read a news article about a "helical engine" design by NASA engineer David Burns. ...
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66 views

Black hole Travel [closed]

Asking out of curiousity. All answers appreciated. You have a machine that generates micro black holes on the outside of it which evaporate quickly and then are immediately generated again upon ...
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Can a Tokamak-Based Mainframe feed Plasma to larger pipe-structure in order to create plasma-based propulsion engines?

Can a Tokamak-Based Mainframe feed Plasma to larger pipe-like structures in order to create plasma-based propulsion engines? It is a rather naive question.
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Feasibility of fin drive

For marine propulsion, propellers/screws are de rigeur. Unfortunately, they are also very hazardous to marine life. I understand that alternatives like water jets and even MHD drives exist, but I am ...
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Deriving the Tsiolkovsky Rocket Equation using the rate at which the fuel burns

I'm trying to understand the derivation of the Tsiolkovsky Rocket Equation. $$\Delta v= \int_{t_0}^{t_1} \dfrac{|T|}{m_0 - t\Delta m}dt$$ The Wikipedia page ...
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Would deuterium or tritium be a better rocket fuel? [closed]

Im not that scientifically literate but through my basics as hell understanding of chemistry is that denser=better wouldn't the denser forms of hydrogen be better for fuel since they would weigh ...
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Is it possible to use Bose-Einstein condensate for propulsion with today's tech?

Can one use the Bose Einstein condensate which we can produce today for space propulsion, as many theoretical concepts need negative mass and that is a property of Bose Einstein condensate, how ...
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Are optimal turbine blades also optimal fan blades?

In one case, the air drives the blade, in the other the blade drives the air. Since each is 'just' the reverse of the other, one might expect that the aerodynamics are the same, with other variables ...
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Simplified calculation of the amount of fuel required for a trip — are my calculations faulty?

I've been always fascinated with how easily scifi characters travel around the Solar system and sometimes the galaxy. They just hop into a spacecar and go wherever they want. So I've come up with a ...
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Why don't spacecraft accelerate to the speed of light, or just fractionally below that?

In space there is almost nothing to slow you down, and your proppelent/S will always be traveling relatively faster than your craft so you should accelerate infinitely close to the speed of light ...
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If fuel was provided by an autonomous side ship, how much fuel would be required for a 10 metric tons rocket to reach the ISS?

The point here is that the rocket weight should never include fuel. It can take off from any departure base of your choice. The fuel provided by the side ship would then be used only to lift the ...
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What percentage of a rocket fuel is used to lift fuel itself?

I don't need an exact number, also it can be to travel to the ISS or the moon, it's not important. I just want to get an idea of how much fuel is used in a «recursive» sort of way. Edit: I am asking ...
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Why don't we use ionized neon for arc jets?

On a typical arc jet there is a cone in the proppelent stream (ammonia or hydrazine) that acts as an anode and the the nozel itself is the cathode. But why don't we use ionized neon as the cathode and ...
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Nuclear Propulsion

I am watching a video on nuclear rocket engines, specifically the Nerva engine. It has a propulsion efficiency of 750-800 Isp versus chemical rockets which are only 350-400 Isp. The follow on NRX ...
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Model Rocket Stabilisation

I am designing a model rocket and am using 3 B6-4 Engines. Inevitably there will be perturbation of its trajectory by wind and engine/thrust inconsistencies. The way that I currently understand the ...
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Can hydrogen plasma react with oxygen?

What if you put hydrogen in a vacuum and turned it into a plasma? There is no oxygen in the vacuum, but once you eject the plasma would it react drastically with the oxygen? Would it explode? Would ...
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Is a rocket engine most efficient when its velocity is equal to the exhaust velocity?

I was reading Dale's answer on this question and from the answer I concluded the following: 1- When the rocket is traveling at a velocity much less than the exhaust speed, most of the chemical energy ...
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Would throwing a heavy object in space work as a form of propulsion?

I watched the "Helping Hand" episode of Love, Death & Robots on NetFlix, where the protagonist is adrift in space. Every second she is further from her ship, and when her tank is out of oxygen, ...
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Derivation of the expression of a propeller pitch distance

The pitch distance of a propeller is given by: $$p = 2\pi r \tan{\beta}$$ where $\beta$ is the pitch angle and $r$ is the radius. I cannot find how this expression was derived. Could you please ...
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How do rocket engines work in EMPTY space? [duplicate]

So I just read this and it didn't make any sense It is not necessary for the rocket exhaust to push against anything EXCEPT THE SHIP ITSELF. You see, when the combustion of fuel takes place ...
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Standing waves in raptor rocket engine test

Stopping the video of the recent test of the raptor rocket engine, one can see a standing wave forming in the exhaust gases: https://youtu.be/MAAzbjG_Duc?t=23 I was wondering what might cause a ...
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Would a horizontally-imbalanced maglev train car be propelled by the force of gravity?

I am wondering if a horizontally-unbalanced maglev train car would be propelled forward by the pull of gravity. This would result from the train car's electromagnets producing unbalanced magnetic ...

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