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Fire detection in a microgravity environment produces a number of concerns. On Earth, smoke particles generated by a fire are often used to trigger an alarm signal. In space, without the thermal buoyancy effects produced by gravity, smoke particle movement is more random, making its detection more difficult. This problem presents itself to the module outfitters who are designing a fire detection system for the Space Station. The volumes behind the racks, referred to as exo-rack areas, are particularly difficult to monitor because they are hidden from view by closeout panels. Still, the exo-rack areas must be monitored because they contain wiring and electrical equipment that presents a potential fire hazard. A strategy for detecting fires in the Space Station exo-rack area has been developed by the McDonnell Douglas Environmental Control and Life Support Systems (ECLSS) team. The system uses piccolo tubes to collect samples of air from the exo-rack areas in the node.

The objectives set forth by NASA's Space Exploration Initiative (SEI) include the construction of a lunar base and the manned exploration of Mars early in the 21st century. However, current life support system technology is not capable of supporting such missions and remains one of the most fundamental limitations of space exploration. To date, life support systems have consisted of exhaustible supplies that limit missions to relatively short durations. This method has sufficed so far; however, if humans are to truly break away from Earth, it will be necessary to reproduce the characteristics of the terrestrial biosphere in extraterrestrial locations. Bioregenerative technology incorporates plants and animals as processors in a regenerative life support system.

Under a presidential directive, the United States has begun preparations to return to the moon. The purpose of this new initiative is not to repeat what the Apollo missions accomplished earlier, but to build on these accomplishments. President Bush has called for a long range continuing commitment to expand human presence beyond Earth orbit. This is a program that will span decades. It will establish a permanent station on the Moon and send a manned mission to Mars. The challenge is to develop the systems and technologies necessary to travel to the Moon and Mars and to provide an environment in which the crew can safely live and work in both of these new worlds. Perhaps the most critical technology to the success of these advanced missions is that related to the basic environmental control and life support system.