Study On The Technology Of Laser Ablation Micro-propulsion Based On The GAP

Micro-thruster is an important component for attitude control,orbital maneuver and maintenance of micro-and nano-satellites. As the rapid development of micro and nano satellites technology, the precision requirement for micro-thruster is more strict. In order to study the technology of micro laser ablation propulsion, the principle conclusions are as follows:(1) In order to measure impulse generated by laser ablation micro thruster accurately, a kind of stand based on the principle of torsion balance was developed, and the influences of damp to test results are analyzed. Studies have shown that, the resolution of the stand is 4.1×10-7 N·s.The impulse measurement range of the system is from 4.1×10-7 N·s to 4.45×10-3 N·s. Damp introduced by air and external lines is very low in 10"3order and resulting measurement error less than 1%.(2) Designed laser ablation micro thrust test prototype based on transmission model (T model). The prototype use diode lasers as light source and export laser with a fiber with a focus function and effective power density acting on ablative materials is 1.27 X 104W/cm2.Energetic polymer Amido Glycidol Ether(GAP) is used as the ablation target material under the static test of the model and the highest impulse coupling coefficient and specific impulse is 247μN/W and 104s, when the thickness of the target tape is 170 microns.(3) Studied the effects of the two kinds of nozzles to impulse. The results show that the existence of conical nozzle makes impulse decreases sharply. The specific impulse is increased effectively when the line type was chosen. The nozzle with the length of 6mm and the inner diameter of lmm affects impulse significantly and makes impulse increased up 25.0%. Due to the larger product particles sputtered, the specific impulse was reduced when nano aluminum powder was added, the largest drop is 47.4%.