Laser plasma thruster continuous thrust experiment

The laser plasma thruster (LPT) is a new microthruster for small satellites. We report on development and testing of a prototype LPT. Some advantages of the LPT are: thruster voltage 4 V, mass less than I kg, power-to-thrust ratio 10 kW/newton and Isp up to 1000 seconds. Typical thrust level is 250 muN with PVC fuel. Thrust of I mN is expected with energetic fuel. The pre-prototype continuous thrust experiment includes the laser mount and heat sink, lens mounts, and focusing mechanism, which are coupled to the target material transport mechanism. The target material is applied to a transparent plastic tape, and the laser is focused on a series of tracks on the tape. The tape drive hardware and laser drive electronics, are described, as well as the control and diagnostic software. Design, construction, and calibration of the thrust stand are described. During continuous operation, the exhaust plume is deflected in the direction of the moving tape. When the laser is operated in pulsed mode, the exhaust plume is perpendicular to the tape (parallel to the optical axis). This provides some thrust vector control.