Survey of Beamed Energy Propulsion Concepts by the MSFC Space Environmental Effects Team

Abstract

Abstract.This will be a survey paper of work that was performed by the Space Environmental Effects Team at NASA's Marshall Space Flight Center in the area of laser energy propulsion concepts.Two types of laser energy propulsion techniques were investigated. The first was ablative propulsion, which used a pulsed ruby laser impacting on single layer coatings and films. The purpose of this investigation was to determine the laser power density that produced an optimum coupling coefficient for each type of material tested. A commercial off-the-shelf multi-layer film was also investigated for possible applications in ablative micro-thrusters, and its optimum coupling coefficient was determined.The second type of study measured the purely photonic force provided by a 300W CW YAG laser. In initial studies, the photon force resulting from the momentum of incident photons was measured directly using a vacuum compatible microbalance and these results were compared to theory. Follow-on work used the same CW laser to excite a stable optical cavity for the purpose of amplifying the available force from incident photons.

Direct Impulse Measurements of Ablation Processes from Laser-Surface Interactions

“…Laser propulsion systems have been extensively discussed since the early 1970s. [5] Laser propulsion concepts range from alternative launch solutions to on-orbit maneuvering or attitude control systems for spacecraft, and have employed an equally diverse range of momentum transfer mechanisms including ablation, shock wave generation [6] , and even photon pressure [7] . The lasers used in these applications also vary in their characteristics from continuous to pulsed beams with powers ranging as low as a few watts to as high as megawatts.…”