送交者: 无知 于 2005-8-09, 14:45:16:
回答: read carefully 由 JZ 于 2005-8-09, 14:37:58:
When a space shuttle lands, there is a possibility that there will be residual fuel in its tanks. The fuel, which consists of hydrazine, methylhydrazine, and ammonia, can be highly flammable and explosive when combined with air. Any large fuel leaks must be detected before the crew can disembark or before support personnel and equipment can enter the shuttle landing area. Building on its basic work in analytical chemistry and chemical microsensors, NRL conceived and developed a detector for fuel vapor concentrations in the explosive range that could be used at the space shuttle's landing site.