우주공간의 압력은 일반적으로 지구로부터의 고도와 대수 관계에 있으며 위성이 비행하는 궤도는 $10^{-6}$-$10^{-11}$torr의 초진공 상태에 가깝고 고도 수십 km까지는 희박기체의 압력으로 볼 수 있으나 그 이상의 고도에서는 기체 분자가 거의 이온이 되어 대단히 고속의 이온 흐름 상태를 유지하고 있다. 우주용 추진기관 개발에 있어서 이와 같은 초고진공에 해당하는 압력을 구현하지 않으면 않되는 시험 이외에도 비교적 고도가 낮은 공간의 SIMULATION에도 중요한 분야이다.

Conventional electroexplosive devices (EED) commonly use a very small metal bridgewire to ignite explosive materials i.e. pyrotechnics, primary and secondary explosives. The use of semiconductor devices to replace “hot-wire” resistance heating elements in automotive safety systems pyrotechnic devices has been under development for several years. In a typical 1 amp/1 watt electroexplosive devices, ignition takes place a few milliseconds after a current pulse of at least 25 mJ is applied to the bridgewire. In contrast, as for a SCB devices, ignition takes place in a few tens of microseconds and only require approximately one-tenth the input energy of a conventional electroexplosive devices. Typically, when SCB device is driven by a short (20 $\mu\textrm{s}$), low energy pulse (less than 5 mJ), the SCB produces a hot plasma that ignites explosive materials. The advantages and disadvantages of this technology are strongly dependent upon the particular technology selected. To date, three distinct technologies have evolved, each of which utilizes a hot, silicon plasma as the pyrotechnic initiation element. These technologies are 1.) Heavily doped silicon as the resistive heating initiation mechanism, 2.) Tungsten enhanced silicon which utilizes a chemically vapor deposited layer of tungsten as the initiation element, and 3.) a junction diode, fabricated with standard CMOS processes, which creates the initial thermal environment by avalanche breakdown of the diode. This paper describes the three technologies, discusses the advantages and disadvantages of each as they apply to electroexplosive devises, and recommends a methodology for selection of the best device for a particular system environment. The important parameters in this analysis are: All-Fire energy, All-Fire voltage, response time, ease of integration with other semiconductor devices, cost (overall system cost), and reliability. The potential for significant cost savings by integrating several safety functions into the initiator makes this technology worthy of attention by the safety system designer.

Combustion characteristics of the solid composite propellants were studied from burning rate, ignition and steady combustion processes, and structure of the extinguished surfaces. Optical Vacuum Strand Burner (OVSB) system was desisted and configured to study those. Burning rates of the propellants were measured by OVSB at low pressure range by developed ten method. video camera(30 frames/s) was used to take potographs of the phenomena of ignition and combustion of propellant within the test cell of the OVSB. Burning surfaces of the propellants that were extinguished by rapid depressurization method were analyzed with Scanning Electron Microscope. (SEM).