SBIR-STTR Award

The growing market for repositioning small satellites requires the development of flexible, energy-efficient, robust but microweight thrusters. Microthruster concepts are scaledowns of conventional thruster designs to very small physical scale, e.g., chemical rockets, pulsed gas thrusters and plasmajets. However, behavior of at small scales is not predicted by behavior at larger scales. We propose a new departure in microthrusters, in which thrust is generated by the plasmajet induced by an onboard high-brightness diode laser focused to a tiny spot on a plane target. No nozzle is required because of electrostatic forces involved in the plasma expansion. No new physics is required at small scales. The energy efficiency of the device is similar to that of pulsed plasma thrusters, and the electronics simpler. Specific impulse Isp is adjustable, and Isp=7000 sec has been measured. The plume produced by this interaction will be a high-velocity, electrically neutral, directed plasma jet, not a cloud of chemical compounds that can condense on the spacecraft. The most difficult part of this project is not making the thruster, but measuring impulses as small as 100 udyn-s [lE-9 n-s] . A mosquito in flight has 10 times this momentum.

Micro and Nano-satellites will be from 100kg to aslittle as 1kg. However, microthrusters which produce the very small minimum impuulse bits (MIB) needed to accurately point these satellites did not exist before we developed our micro laser plasma thruster (uLPT) in Phase I. The uLPT is an efficient, long life, low-thrust pulsed rocket engine which uses a high brightness semiconductor or glass fiber laser as as a source of energy. It uses a simple low voltage semiconductor switch to drive the laser without using any electrical power in the off state. A len brings the laser light output to a target within a very small spot, producing a spark or miniature jet, which provides the impulse. In Phase II, we will design , build and space-quality a prototype laser plasma thruster (LPT). We will optimized those features that enable the resulting thruster to be the best solution to teh problem of orienting and maintaining orientation of micro- and nanosatellites. We will then prepare to be a supplier for these for these thrusters, to satisfy a market which we anticipate will increase to the total $64M by CY2010.