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Author Topic: Could Plasma be used to propel a space shuttle?  (Read 795 times)

Offline PhysicsGamer

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Could Plasma be used to propel a space shuttle?
« on: 15/08/2016 18:12:04 »
I would like to hear your thoughts on this propulsion system that I designed. The designs are quite crude, but they show the general concept. The general idea is that when electricity goes through a gas, it makes plasma, if that plasma was allowed to build up, it could be released to produce a short burst of thrust.


 

Offline Bored chemist

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Re: Could Plasma be used to propel a space shuttle?
« Reply #1 on: 15/08/2016 20:35:47 »
Plasma is used to propel the space shuttle.
Any hot gas will be (at least partly ) ionised- even a candle flame is a weak plasma.

The problem with your system is that the battery would need to be very heavy and it wouldn't produce enough thrust to lift itself very far.
 
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Offline PhysicsGamer

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Re: Could Plasma be used to propel a space shuttle?
« Reply #2 on: 15/08/2016 20:40:24 »
Yes, it would be ineffective for attempting to escape Earth's atmosphere, although it may be effective for travel through a zero-gravity situation.
 

Offline PhysicsGamer

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Re: Could Plasma be used to propel a space shuttle?
« Reply #3 on: 15/08/2016 20:56:41 »
Yes, it would be ineffective for attempting to escape Earth's atmosphere, although it may be effective for travel through a zero-gravity situation.
It would be particularly effective for a gravity-slingshot.
 

Online evan_au

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Re: Could Plasma be used to propel a space shuttle?
« Reply #4 on: 15/08/2016 22:30:54 »
Quote from: PhysicsGamer
if that plasma was allowed to build up, it could be released to produce a short burst of thrust.
The Specific Impulse of a rocket (or the amount of "push" you can get from the rocket's reaction mass)  is determined by the velocity of the particles.

Rather than use a battery to heat up a gas (only to have the heat quickly leak away), you can use electricity (an electric field) to accelerate charged ions to extremely high velocities. These velocities only occur in a plasma hot enough to melt steel.

To avoid taking heavy batteries with you, you can harvest electrical energy from the Sun with solar cells.

NASA has been working with a company developing a powerful ion rocket that was to be used for maintaining the orbit of the ISS. But it would have taken a lot of the energy from the ISS solar cells while it was running.

Smaller ion thrusters have been used on a number of space missions:
https://en.wikipedia.org/wiki/Ion_thruster
 

Offline PhysicsGamer

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Re: Could Plasma be used to propel a space shuttle?
« Reply #5 on: 15/08/2016 22:43:40 »
I wasn't talking about using heat on the gas, I was talking about using electricity on the gas.
 

Online evan_au

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Re: Could Plasma be used to propel a space shuttle?
« Reply #6 on: 16/08/2016 22:47:29 »
Quote from: PhysicsGamer
I wasn't talking about using heat on the gas, I was talking about using electricity on the gas.
From the diagram, it looks like there is a closed "chamber for plasma to be created and stored".
There is a valve to admit liquid oxygen into this chamber, which is then subjected to "a large amount of electricity".

Oxygen is an insulator, so the only way electricity can flow is to strike an electrical arc (or have it flow through a heating element).
- The electrical arc heats up the liquid oxygen until it boils, and keeps heating until it becomes a plasma.
- The result is a rise in temperature, which produces a corresponding rise in pressure.
- There is an exit valve to allow the pressure to escape, propelling the spacecraft.
- The thrust of this engine is determined by the velocity of the oxygen ions, ie how effectively you can turn a temperature rise (random velocities of ions) into a rocket jet (uniform velocity of ions).

There are severe problems with trying to maintain a hot plasma at high temperatures (eg see discussion in  another thread). It tends to cool down quickly and/or burn through the container walls.

So you actually want to create the plasma with all the ions traveling in the desired direction, and to hold the plasma for the shortest possible time; an ion rocket does both of these, and is able to achieve quite high efficiency (for a rocket).
 

Offline agyejy

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Re: Could Plasma be used to propel a space shuttle?
« Reply #7 on: 16/08/2016 23:31:35 »
The professionals that are paid to do propulsion design have already had this idea:

https://en.wikipedia.org/wiki/Plasma_propulsion_engine
 

Offline William McC

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Re: Could Plasma be used to propel a space shuttle?
« Reply #8 on: 17/08/2016 11:58:39 »
If you inject a liquid into a helium plasma in very small quantities you can achieve pressures well over 150,000 psi and beyond. So yes a plasma can be part of a very powerful very effective propulsion system. It has already been proven to work well in air or in space.

It also offers anyone a vehicle to transport weapons very quickly from anywhere on earth to anywhere in the solar system and beyond very quickly. It was deemed too dangerous by the government. Usually the people that have enough money and time to build systems are cut off from the deep defense spending pockets, once they go public or try to push the product.

Sincerely,

William McCormick 
 

Offline William McC

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Re: Could Plasma be used to propel a space shuttle?
« Reply #9 on: 17/08/2016 12:02:45 »
When you create a temperature and pressure differential over 150,000 psi the electrical differential created is extreme. This can be harvested to charge the batteries to create the plasma and power the ship. But creating electrical power is not a problem for the same people that have already been building these systems for over 70 years.

NASA is just not up to the politics of poverty.


Sincerely,

William McCormick
 

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Re: Could Plasma be used to propel a space shuttle?
« Reply #9 on: 17/08/2016 12:02:45 »

 

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