Abstract : Microthrusters are useful for orienting and repositioning small craft above the atmosphere. We report technical results obtained during a successful 5-year program to develop a commercially-viable laser-powered microthruster. Its main advantage is the ability to generate a broad thrust range under programmable electronic control with minimal electrical power. The device applies millisecond-duration diode-laser pulses to a fuel tape to produce an ablation jet. By employing laser-initiated energetic polymers in our ablation fuel tapes, we obtained momentum coupling coefficients as large as 2.0mN/W of incident laser power, giving a continuous thrust range from 50 N to 10mN. With our standard 30m x 8mm fuel tape, fueled thruster mass is 0.4kg and 40N-s lifetime impulse is achieved. With an order-of-magnitude greater fuel mass, the thruster could accomplish re-entry or substantial orbit-raising of a 10-kg microsatellite. In its usual configuration, specific impulse is 200 seconds, and ablation efficiency, the ratio of exhaust kinetic energy to incident laser optical energy is 180%. We compare performance of several laser-initiated micropropellants which we studied, including polyvinyl nitrate (PVN), glycidyl azide polymer (GAP), and nitrocellulose (NC). All were doped with a laser-absorbing component, either carbon nanopearls with 10nm mean diameter or dyes tuned to the 920-nm laser wavelength but transparent at visible wavelengths. Our demonstrated momentum coupling coefficient is sufficient to levitate a 0.1-kg object with a 400-W laser beam having appropriate characteristics.
[1]
Matthew Peters,et al.
High-power high-efficiency 910- to 980-nm broad-area laser diodes
,
2004,
SPIE LASE.
[2]
H. Bruce Land,et al.
Instrumentation Development for Micro Pulsed Plasma Thruster Experiments
,
2005
.
[3]
Juergen Mueller,et al.
Thruster Options for Microspacecraft: A Review and Evaluation of State-of-the-Art and Emerging Technologies
,
2000
.
[4]
Claude R. Phipps,et al.
3ks Specific Impulse with a ns-pulse Laser Microthruster
,
2005
.
[5]
Bernd Sumpf,et al.
High-brightness diode lasers
,
2003
.
[6]
Claude R. Phipps.
Will your children ride a laser beam into orbit? Would you want them to? — Realistic applications of ablative laser propulsion
,
2005
.
[7]
A. Wokaun,et al.
Giant Momentum Coupling Coefficients from Nanoscale Laser-initiated Exothermic Compounds
,
2005
.
[8]
Mariano Andrenucci,et al.
Qualification Status of the FEEP-150 Electric Micropropulsion Subsystem
,
2005
.