NASA will be sending the variable specific impulse magnetoplasma rocket (Vasimr) up to the International Space Station (Paid subscription required) for tests and validation. (Earlier posts)

It’s expected to put out about 5.7 Netwons, about a pound, with an ISP (fuel economy) of somewhere between 10 and 30 times that of chemical propellants.

While a pound does not seem like much thrust, it’s more than enough for station keeping and orbital, or for that matter interplanetary, maneuvering, as you can get the thrust for months, rather than hours, and compared to other electric thrusters systems, like the ion drive used on the Dawn Probe, it provides a lot more thrust. (Dawn has a thrust of only 90mN, about 1/50 that of the Vasimr).