Performance of Systems

In this area, some concepts have already been sketched out which are intended to particularly exploit the capabilities of MNT. [6] examines lightsails, which are propelled by the light pressure from the sun on a large surface, and solar-powered ion engines, which turn solar energy into electrical power and use that power to accelerate ions to high exhaust velocities. (The accelerated ions are neutralized before release so that the vehicle does not build up a net charge.) As discussed, an unloaded sail 20 nm thick of aluminum will develop an acceleration of up to 0.16 m/s², depending on its solar angle, at one AU from the sun. This is equivalent to a 0.08 m/s² acceleration with a payload mass equal to the sail mass, or a 0.04 m/s² acceleration with a payload mass equal to three times the sail mass. A major advantage of solar sails (built with or without MNT) is that they can provide this thrust continuously, without expending on-board reaction mass.

The ion engine discussed in [6] uses solar collectors with specific power on the order of nearly 10⁵ W/kg to drive ion engines with a ~250,000 m/s ideal exhaust velocity, providing ~0.8 m/s² acceleration. [2], suggests the specific power could be more than an order of magnitude greater, and a 1,000,000 m/s ideal exhaust velocity vehicle could provide ~9.8 m/s² acceleration.