Author Topic: VASIMR Engine  (Read 156183 times)

Offline Stormbringer

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Re: VASIMR Engine
« Reply #80 on: 12/21/2014 10:52 PM »
They have done a lot of work on the VASIMR.

No doubt. What they haven't done is produce a rocket engine.
it is my understanding that the VF 200 is fully built and ground tested. what does it take other than that to "produce a rocket engine?"

http://upload.wikimedia.org/wikipedia/en/3/36/VX-200_operation_full_power.jpg

« Last Edit: 12/21/2014 10:58 PM by Stormbringer »
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Offline QuantumG

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Re: VASIMR Engine
« Reply #81 on: 12/21/2014 10:58 PM »
it is my understanding that the VF 200 is fully built and ground tested. what does it take other than that to "produce a rocket engine?"

We've been through this. They haven't demonstrated exhaust separation. It doesn't produce thrust. After 37 years, that's pretty impressive!
I hear those things are awfully loud. It glides as softly as a cloud. What's it called? Monowhale!

Offline Stormbringer

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Re: VASIMR Engine
« Reply #82 on: 12/21/2014 10:59 PM »
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Offline QuantumG

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Re: VASIMR Engine
« Reply #83 on: 12/21/2014 11:02 PM »
What's your point? A rocket engine produces thrust. The VASIMR engine doesn't. My plasma cutter looks pretty impressive too but it's not a rocket engine. That's what they've produced: a plasma show.
I hear those things are awfully loud. It glides as softly as a cloud. What's it called? Monowhale!

Offline Stormbringer

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Re: VASIMR Engine
« Reply #84 on: 12/21/2014 11:05 PM »
it is my understanding that the VF 200 is fully built and ground tested. what does it take other than that to "produce a rocket engine?"

We've been through this. They haven't demonstrated exhaust separation. It doesn't produce thrust. After 37 years, that's pretty impressive!

So NASA agreed to send a engine to space that produces no thrust? I don't think so. That does not sound likely.
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Offline QuantumG

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Re: VASIMR Engine
« Reply #85 on: 12/21/2014 11:07 PM »
So NASA agreed to send a engine to space that produces no thrust? I don't think so. That does not sound likely.

That's the point of the test. To demonstrate exhaust separation. Also, NASA agreed to no such thing. Again, you're a sucker for press releases.
« Last Edit: 12/21/2014 11:10 PM by QuantumG »
I hear those things are awfully loud. It glides as softly as a cloud. What's it called? Monowhale!

Offline RonM

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Re: VASIMR Engine
« Reply #86 on: 12/21/2014 11:20 PM »
it is my understanding that the VF 200 is fully built and ground tested. what does it take other than that to "produce a rocket engine?"

We've been through this. They haven't demonstrated exhaust separation. It doesn't produce thrust. After 37 years, that's pretty impressive!

I don't recall being through this. Please elaborate why you say VASIMR doesn't produce thrust and site your sources.

Offline QuantumG

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Re: VASIMR Engine
« Reply #87 on: 12/21/2014 11:29 PM »
I don't recall being through this. Please elaborate why you say VASIMR doesn't produce thrust and site your sources.

http://forum.nasaspaceflight.com/index.php?topic=18382.msg487159#msg487159

If you want a source, how about this unfunded grant application for demonstrating plasma detachment: http://www.uh.edu/research/spg/uhdiagnostics.html

Or Ad Astra's computer simulation paper: http://www.adastrarocket.com/AndrewASS02.PDF

Quote
The described particle simulations in VASIMR
demonstrate plasma detachment from the magnetic
nozzle. Reasonable agreement between MHD and
particle simulation is observed in plasma beta
detachment analysis. The codes developed so far are
being validated in the VX-10 laboratory experiment
and assisting researchers in the design of a VASIMR
flight demonstration experiment.

There's no dispute, Ad Astra have yet to demonstrate that VASIMR produces thrust. They expect to demonstrate that on a flight mission, which hasn't been funded and for which no launch has been allocated.
« Last Edit: 12/21/2014 11:40 PM by QuantumG »
I hear those things are awfully loud. It glides as softly as a cloud. What's it called? Monowhale!

Offline Stormbringer

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Re: VASIMR Engine
« Reply #88 on: 12/21/2014 11:38 PM »
I think anything that poops anything out one end (even if it's just blue glowy stuff) produces thrust. Even a rocket powered by beer is possible.

I believe the early early early VASIMR prototype produced 5 newtons at 67 percent efficiency. Now that does appear weak but its on the order of other ion engines; thrust-wise.

EDIT: Thrust was calculated at 5N. it was not tested WRT actual thrust.
« Last Edit: 12/21/2014 11:50 PM by Stormbringer »
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Offline Stormbringer

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Re: VASIMR Engine
« Reply #89 on: 12/21/2014 11:48 PM »
it looks like QuantumG is *technically* correct.

http://en.wikipedia.org/wiki/Variable_Specific_Impulse_Magnetoplasma_Rocket

Quote
One of the remaining untested issues was potential vs actual thrust; that is, whether the hot plasma actually detached from the rocket.

However; the notion that VASIMR will not work because of this seems ridiculous. i see little difference between VASIMR and countless other ion or plasma rockets.
« Last Edit: 12/21/2014 11:49 PM by Stormbringer »
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Offline RonM

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Re: VASIMR Engine
« Reply #90 on: 12/22/2014 12:22 AM »
I don't recall being through this. Please elaborate why you say VASIMR doesn't produce thrust and site your sources.

http://forum.nasaspaceflight.com/index.php?topic=18382.msg487159#msg487159

If you want a source, how about this unfunded grant application for demonstrating plasma detachment: http://www.uh.edu/research/spg/uhdiagnostics.html

Or Ad Astra's computer simulation paper: http://www.adastrarocket.com/AndrewASS02.PDF

Quote
The described particle simulations in VASIMR
demonstrate plasma detachment from the magnetic
nozzle. Reasonable agreement between MHD and
particle simulation is observed in plasma beta
detachment analysis. The codes developed so far are
being validated in the VX-10 laboratory experiment
and assisting researchers in the design of a VASIMR
flight demonstration experiment.

There's no dispute, Ad Astra have yet to demonstrate that VASIMR produces thrust. They expect to demonstrate that on a flight mission, which hasn't been funded and for which no launch has been allocated.

Thanks for the quick and thorough response. After looking at those links, I found a paper from January 2014.

http://w3fusion.ph.utexas.edu/ifs/ifsreports/977_Arefiev.pdf

Looks like they are still working on it a decade after the first proposal.
« Last Edit: 12/22/2014 12:37 AM by RonM »

Offline A_M_Swallow

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Re: VASIMR Engine
« Reply #91 on: 12/22/2014 02:03 AM »
To spend money on something NASA has to go through complex bureaucratic processes.  This includes making announcements and issuing requests for bids.  Have a look at the small print in the NextSTEP Broad Agency announcement thread.

"Advanced Concepts
Next Space Technologies for Exploration Partnerships (NextSTEP) BROAD AGENCY

http://forum.nasaspaceflight.com/index.php?topic=36273.0"


Ref to NASA document
https://prod.nais.nasa.gov/eps/eps_data/163051-SOL-001-001.pdf

That engine specification sounds like a VASIMR.
« Last Edit: 12/22/2014 02:04 AM by A_M_Swallow »

Offline Raj2014

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Re: VASIMR Engine
« Reply #92 on: 12/23/2014 11:20 PM »
it is my understanding that the VF 200 is fully built and ground tested. what does it take other than that to "produce a rocket engine?"

We've been through this. They haven't demonstrated exhaust separation. It doesn't produce thrust. After 37 years, that's pretty impressive!

Here is a video showing a engine producing thrust.

Offline QuantumG

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Re: VASIMR Engine
« Reply #93 on: 12/23/2014 11:54 PM »
it is my understanding that the VF 200 is fully built and ground tested. what does it take other than that to "produce a rocket engine?"

We've been through this. They haven't demonstrated exhaust separation. It doesn't produce thrust. After 37 years, that's pretty impressive!

Here is a video showing a engine producing thrust.

No it isn't.

Go to your kitchen sink, fill it with water and swirl your hand around to create a vortex. Now stick a large flat spoon into the flow. You will feel a force, that's momentum response. To claim that your setup is producing net force would be silly, but to do it you'd need to make an argument about the detachment of the medium from the vessel. That is, you need to pull out the plug. As far as I'm aware, Ad Astra have never claimed they could demonstrate detachment of the plasma from the nozzle on the ground and have no plans to do so.
I hear those things are awfully loud. It glides as softly as a cloud. What's it called? Monowhale!

Offline momerathe

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Re: VASIMR Engine
« Reply #94 on: 12/24/2014 07:53 PM »
As far as I'm aware, Ad Astra have never claimed they could demonstrate detachment of the plasma from the nozzle on the ground and have no plans to do so.
I don't think there's a vacuum chamber big enough.
thermodynamics will get you in the end

Offline manboy

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Re: VASIMR Engine
« Reply #95 on: 12/24/2014 08:33 PM »
it is my understanding that the VF 200 is fully built and ground tested. what does it take other than that to "produce a rocket engine?"

We've been through this. They haven't demonstrated exhaust separation. It doesn't produce thrust. After 37 years, that's pretty impressive!
Well given enough time maybe XCOR will beat that record.
"Cheese has been sent into space before. But the same cheese has never been sent into space twice." - StephenB

Offline Garrett

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Re: VASIMR Engine
« Reply #96 on: 12/24/2014 09:02 PM »
I think anything that poops anything out one end (even if it's just blue glowy stuff) produces thrust.
You would be thinking wrong then. Plasma "poop" is made up of charged particles. If you just shoot out positive ions then a massive electric field will form that will be strong enough to pull those ions back to the rocket, thereby cancelling all thrust. That's why ion thrusters also have electron guns, to neutralize the ions, allowing them to leave the rocket system as neutral atoms.
Vasimr doesn't use such a neutralizing mechanism. In fact, I've never quite understood how the ions were to be neutralized efficiently. That's what will define how well the ions detach and whether their blue glowy stuff has any kick to it.
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Offline Raj2014

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Re: VASIMR Engine
« Reply #97 on: 12/24/2014 09:12 PM »
it is my understanding that the VF 200 is fully built and ground tested. what does it take other than that to "produce a rocket engine?"

We've been through this. They haven't demonstrated exhaust separation. It doesn't produce thrust. After 37 years, that's pretty impressive!

Here is a video showing a engine producing thrust.

No it isn't.

Go to your kitchen sink, fill it with water and swirl your hand around to create a vortex. Now stick a large flat spoon into the flow. You will feel a force, that's momentum response. To claim that your setup is producing net force would be silly, but to do it you'd need to make an argument about the detachment of the medium from the vessel. That is, you need to pull out the plug. As far as I'm aware, Ad Astra have never claimed they could demonstrate detachment of the plasma from the nozzle on the ground and have no plans to do so.

You say the VASIMR does not produce thrust, yet in the video I posted, we can see the VASIMR move the Momentum/Impulse response target.

Offline QuantumG

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Re: VASIMR Engine
« Reply #98 on: 12/24/2014 09:20 PM »
it is my understanding that the VF 200 is fully built and ground tested. what does it take other than that to "produce a rocket engine?"

We've been through this. They haven't demonstrated exhaust separation. It doesn't produce thrust. After 37 years, that's pretty impressive!

Here is a video showing a engine producing thrust.

No it isn't.

Go to your kitchen sink, fill it with water and swirl your hand around to create a vortex. Now stick a large flat spoon into the flow. You will feel a force, that's momentum response. To claim that your setup is producing net force would be silly, but to do it you'd need to make an argument about the detachment of the medium from the vessel. That is, you need to pull out the plug. As far as I'm aware, Ad Astra have never claimed they could demonstrate detachment of the plasma from the nozzle on the ground and have no plans to do so.

You say the VASIMR does not produce thrust, yet in the video I posted, we can see the VASIMR move the Momentum/Impulse response target.

Which I just explained to you. I'm not sure what more I can do.
I hear those things are awfully loud. It glides as softly as a cloud. What's it called? Monowhale!

Offline Adaptation

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Re: VASIMR Engine
« Reply #99 on: 12/25/2014 06:14 AM »
You say the VASIMR does not produce thrust, yet in the video I posted, we can see the VASIMR move the Momentum/Impulse response target.

Imagine ping pong balls attached to a board by rubber bands.  You make a fancy mechanism that will shoot them out really fast but unless you cut the rubber band they will come back and no net thrust will be produced.  Such a device could move a 'Momentum/Impulse response target' and still be useless in space.  I'm in no position to argue one way or the other but maybe it will help you understand QuantumG's take on the thing. 

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