Preliminary study of counter impact with two-stage light gas gun using electrothermal–chemical gun technology

Recently, hypervelocity impacts between space structures and space debris have been brought to attention with the advance of space development. The impact velocity at low earth orbit (LEO) is up to 15 km/s. Such impact velocity cannot be attained by the current two-stage light gas gun (TSLGG). Therefore we have a plan of counter impacts that used two sets of TSLGGs in order to raise impact velocity. There are three problems in order to realize the counter impacts. They are launch timing, recovery of target and alignment of gun axis. In this research, we considered launch timing of TSLGG among them. It is important to control variation of delay time from propellant ignition to projectile launch in the counter impacts. In a conventional TSLGG, combustion rate changes every time and impact position will vary widely. In order to stabilize combustion rate, we developed a new TSLGG that used the technology of electrothermal–chemical (ETC) gun for its 1st stage. In a conventional TSLGG, the variation of delay time is 20–30 ms. On the other hand, in a new TSLGG, we have succeeded in suppressing the delay time variation less than 200 μs. It is concluded that the TSLGG based on the technology of ETC gun is effective to control the delay time in this paper.