Development of GAP/AP Solid Propulsion System for Ultra-Small Satellite

摘要

The purpose of this work is to develop the small solid propulsion system using Glycidyl Azide Polymer (GAP)/ Ammonium Perchlorate (AP) propellant for an ultra-small satellite. The study approached three parts; the selection of the propellant, the investigation of its combustion characteristic, and the Verification of the propulsion system performance. At first, solid rocket was selected as suitable for the ultra-small propulsion system. The system demands the use of one-time-only, the condition of being small size as possible, and the stably stored and stable ignition. Especially, GAP/AP propellant is the most suitable propellant in terms of both performance and manufacturing because of its higher density specific impulse compared to conventional solid propellant. The propellants manufactured of 30wt%GAP and 70wt%AP have an enough viscosity and degassing which means good manufacturability. The combustion characteristic, the relationship of burning rate, and combustion pressure approximately correspond with previous work. In this study, the burning rate on GAP30/AP70 and cured GAP was obtained 18.3 mm/s @ 5 MPa and 17.2 mm/s @ 5 MPa, respectively. Finally, the small propulsion system was designed for the verification of its performance. The small solid motor is made of cylindrical Bakelite tube ф 29 x 30 mm and predicted 9.8 Ns as total impulse and 230 s as specific impulse. And, the ground firing test was conducted in atmospheric pressure and succeeded with a smooth ignition. Reproducibility of the thrust data of this propulsion system has been satisfactory. However, lower performance is obtained than predicted value; 83% lower total impulse and 13% lower specific impulse. One of the reasons is caused by the different of vacuum condition on this ground firing test. The other is that the burning was quenched in a middle of combustion. The reason seems to be that the AP particle distribution is ununiformity in the propellant. The paper presents the results of each in