SBIR-STTR Award

BMDO has a critical need for advancements in propulsion to achieve major reductions in the costs of placing and maintaining payloads in desired locations. In particular, efficient launch systems for small technological payloads and advances in small thrusters propulsion systems are needed, and these require revolutionary, new aerospace propulsion-related technologies. The micro Laser Plasma Thruster (uLPT) which Photonic Associates originated is such a technology. Our uLPT uses a cluster of diode lasers focused to a 50mm spot on the back of a transparent tape coated with a 50mm-thick carbon-containing absorbing layer. As the tape moves across the laser focus, a high-temperature jet is created on the opposite side from the laser without burning through the tape. This is called "transmission mode" illumination. Under earlier Air Force funding, we developed and tested a preprototype thruster which exceeded the TechSat 21 requirement of 75mN thrust per axis. Technical issues which remain include "reflection" vs. "transmission" modes of target illumination and minimizing outgassing of ablation coatings. In this Phase I effort, we will address remaining technical issues and design a commercially viable prototype thruster to be built under Phase II. The laser-driven engine we propose will have 200µN thrust, 30W power requirement, and total mass 0.75kg. This effort will lead to Phase II development of the first laser-driven microthruster. Its applications are precise positioning and orientation of micro- and nano-satellites in constellations such as TechSat 21.

Keywords:
PLASMA, MICROTHRUSTER, MICROSATELLITE , MICROPROPULSION, LASER, NANOSATELLITE

There exists a critical need for revolutionary, new aerospace propulsion-related technologies. The micro Laser Plasma Thruster (uLPT) which Photonic Associates originated is such a technology. Our uLPT uses a cluster of diode lasers focused to a 25mm spot on the back of a transparent tape coated with a 50mm-thick carbon-containing absorbing layer. As the tape moves across the laser focus, a high-temperature jet is created on the opposite side from the laser without burning through the tape. Under earlier funding, we developed and tested a preprototype thruster which exceeded the TechSat 21 requirement of 75mN thrust per axis. We discovered that the thrust axis could be steered 60 degrees in 10 ms by changing the electrical drive parameters. In this Phase II effort, we will build and test two copies of a rugged testbed micro laser plasma thruster. These devices will use our proprietary coating technology to generate 500 seconds specific impulse and 500 micronewtons per watt of laser light. One copy will go to AFRL Edwards for use in their micropropulsion program. We will test the other copy using both their and our laboratory facilities. Subsequently, we will use the information gained to design, build and test two copies of a commercializable prototype.

Keywords:
Micropropulsion, Subkilogram, Diode Laser, Coupling Coefficient, 100 Micronewton