NASA will test the Variable Specific Impulse Magnetoplasma Rocket (VASIMR) plasma engine on their space station

It promises something in excess of 40 times the specific impulse (fuel efficiency) of chemical rockets, and its thrust is a lot higher than alternate technologies, something on the order of about 10N (around 2 lbs) as opposed to the millinewton thrust levels of ion engines.

It should be interesting.

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