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Josh Cryer

Moderator

Registered: 2001-09-29

Posts: 3,830

Re: Mini-Magnetospheric Plasma Propulsion - Relatively new concept.

So, I was buggin around the other day, trying to find out the most efficient fuelless design for a space ship, and I came upon something called Mini-Magnetospheric Plasma Propulsion, or M2P2 for short.

Basically, the idea is this. Take a magnetic feild, squirt some plasma in it to blow it up, and hope that the solar wind will push ya. Well, the idea is okay, but since the solar wind is so low ( 1/10,000 that of light! ) it's not really that effective. Even for a mini-magnetosphere that's 30 kilometers across. So to make it more efficient you simply throw some absorbant (or reflective) particles into the plasma stream to exploit light pressure. Instead of me rambling, I'll just post some sources.

Slide show: http://cspar181.uah.edu/RbS/HTML/PHY00/img0.htm

Robert Sheldons paper on dusty plasma sails: http://cspar181.uah.edu/RbS/PAPER/STAIF02/index.html

M2P2 homepage: http://www.geophys.washington.edu/Space … odel/M2P2/

Thoughts?

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Some useful links while MER are active. [url=http://marsrovers.jpl.nasa.gov/home/index.html]Offical site[/url] [url=http://www.nasa.gov/multimedia/nasatv/MM_NTV_Web.html]NASA TV[/url] [url=http://www.jpl.nasa.gov/mer2004/]JPL MER2004[/url] [url=http://www.spaceflightnow.com/mars/mera/statustextonly.html]Text feed[/url]
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The amount of solar radiation reaching the surface of the earth totals some 3.9 million exajoules a year.

Phobos

Member

Registered: 2002-01-02

Posts: 1,103

Re: Mini-Magnetospheric Plasma Propulsion - Relatively new concept.

Fascinating concept.  It certainly beats trying to make kilometer after kilometer of materials that are only a few atoms thick.  It's also interesting how the plasma field would grow in size proportionate to its distance from the sun.  It's kinda like flying around in a giant dust bunny.   I wonder what the optimum density of the dust field would have to be though in order to get any meaningful transfer of momentum from light.  It could be like flying a solar sail with more holes than sail.  That could be an issue if the craft attempts to travel to areas at the edge of the solar system where the solar wind thins out significantly.

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To achieve the impossible you must attempt the absurd

Josh Cryer

Moderator

Registered: 2001-09-29

Posts: 3,830

Re: Mini-Magnetospheric Plasma Propulsion - Relatively new concept.

Given everything I know about this. I think it's the only viable fuelless design, unless it turns out to be infeasible... as of now, the concept is sound, but there is still the question as to whether or not you can maintain a dusty plasma megnetosphere at high velocity.

Regular solar sails are not within our reach, and will not be within our reach for quite awhile, if ever. The sail itself, to be effective, has to be less than 5g per square meter. I don't see it happening any time soon, if ever.

If you read the slideshow it's possible to make the absorbant (or reflective) particles follow a 2D path, like the rings of Saturn. So you could have a huge plasma field (which also acts as passive shielding) that contains a ring of reflective material hundreds of miles across. Being held together by the magnetic field. Beautiful concept, really.

The question does remain as to whether or not it can hold together, but I think it's entirely possible if they use superconducting magnets.

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Some useful links while MER are active. [url=http://marsrovers.jpl.nasa.gov/home/index.html]Offical site[/url] [url=http://www.nasa.gov/multimedia/nasatv/MM_NTV_Web.html]NASA TV[/url] [url=http://www.jpl.nasa.gov/mer2004/]JPL MER2004[/url] [url=http://www.spaceflightnow.com/mars/mera/statustextonly.html]Text feed[/url]
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The amount of solar radiation reaching the surface of the earth totals some 3.9 million exajoules a year.

Tom Jolly

Banned

Registered: 2002-05-05

Posts: 40

Re: Mini-Magnetospheric Plasma Propulsion - Relatively new concept.

The ACE spacecraft (http://www.ips.gov.au/asfc/current/bzspeed.html) measured the solar wind at 630km/s (it varies a lot), which is about 1/500th light speed, a lot higher than quoted. Also, you could increase your vehicle speed beyond the speed of the solar wind by tilting your solar sail at a steep angle with respect to the wind (opinion, not fact).

Phobos

Member

Registered: 2002-01-02

Posts: 1,103

Re: Mini-Magnetospheric Plasma Propulsion - Relatively new concept.

How would you slow something like a plasma sail down so you could put it in orbit or whatever?  With a solar sail you can just bounced the light around to slow it down, but you couldn't really control the light well with a horde of dust.  I guess you could alter the magnetic field to do it but I wonder if you'd be able to hold onto all that dust despite the dust's inertia.

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To achieve the impossible you must attempt the absurd