2000 NASA STTR Phase-I Proposal
Proposal #: 000022 

1. Research Topic: 04 - Space Propulsion
2. Project Title: Carbon Sails for Gossamer Spacecraft Attitude Control

3. Small Business Concern                        4. Principal Investigator
   Name:     Energy Science Laboratories, Inc.      Name: Timothy Knowles
   Address:  6888 Nancy Ridge Drive
   City:     San Diego 
   ST:       CA Zip: 92121

5. Research Institution 
   Name:     Univ of Kentucky Research Foundation 
   Address:  102 Kinkead Hall
   City:     Lexington
   ST:       KY Zip: 40506

6. Technical Abstract (Limit 200 words)

It is well known that light and other electromagnetic radiation can exert pressure on matter, which is the basis for photon sail propulsion. Less well known is that light can also exert controlled torque and in-plane tension on sails that have suitable electromagnetic properties. Although these effects are potentially effective aids to deployment and remote control of gossamer spacecraft, they have not been investigated either analytically or experimentally. This project shall investigate these effects with the goal of developing materials, design tools, and gossamer spacecraft control strategies. Phase 1 will analyze the thrust, tension, and torque produced when polarized electromagnetic radiation interacts with anisotropic sails. Experiments will be performed on tailored carbon microtruss sails using an ultra-sensitive vacuum torsion wire technique to directly measure low-power microwave radiation pressure and torque. Advanced sail designs will be drafted and applications to gossamer spacecraft control will be assessed. Phase 2 would further develop the technology, including numerical and analytical methods, carbon sail processing, and ground testing in vacuum at low power. Concepts for experiments in microgravity (parabolic flight) and at higher power will be developed.

7. Potential Commercial Application(s)(Limit 200 words)

The proposed sails offer novel flight control for sails and gossamer spacecraft. The potential exists to provide long-term attitude control for gossamer spacecraft without consumption of on-board fuel, which would greatly reduce the cost of launching and maintaining earth-orbiting satellites. The development may be useful for control of space interferometer spacecraft that require precision formation. The carbon materials also have application to lightweight large-area microwave spacecraft antennas as well as wireless handsets with novel directional and polarization-sensitive properties.