Ovetvieiv 



to Earth's when life arose. Because the record of environmental conditions on Mars 

 during its first billion years is potentially far better preserved than that of early 

 Earth, samples from the planet collected by automated reconnaissance could fill the 

 gap in Earth's geological record. 



The Viking spacecraft, which landed on Mars in 1976 and transmitted data from the 

 planet to Earth until 1982, showed no evidence of life or organic matter at two land- 

 ing sites. This information, however, is not necessarily representative of the planet 

 as a whole, and it does not address the possible existence of fossil organisms. Some 

 indication of the former presence of life may be obtained by machines. Robotic sur- 

 face reconnaissance could survey terrain where water may have existed in the past. 

 In the process, it could probably identify strata of limestone or other minerals and 

 organic compounds that are associated with biological activity on Earth and, in 

 addition, possibly provide an early indication that Mars once harbored life. 



Any valid indication of life on Mars would be a major scientific discovery. It would 

 confirm the perception of many exobiologists that life is a nearly inevitable conse- 

 quence of chemical evolution on any planet where environmental conditions are 

 favorable, and it would have large implications for future research. 



There is a fundamental human urge to know who we are, how we came to exist, 

 what our place is in the universe, whether we can live elsewhere in the solar sys- 

 tem, if we are alone. The scientific inquiry conducted by NASA Life Sciences pro- 

 grams into these questions is considered further in the following parts of section 3: 

 "Controlled Ecological Life Support Systems," "Biospherics Research," and 

 "Exobiology." 



Flight Programs 



The responsibilities of Flight Programs are to develop the equipment, facilities, 

 expertise, and flight opportunities needed to assure successful conduct of life 

 sciences investigations in space, to transfer knowledge gained from space flight to 

 the larger research community, and to develop new technologies and equipment 

 for future research conducted on the ground and in space. Its greatest current task 

 is to see that a sufficient number and variety of flight opportunities are made avail- 

 able for life sciences investigations. 



During the first half of the 1980's, Flight Programs concentrated on life sciences 

 research for the Space Shuttle. An extensive inventory of laboratory equipment was 

 developed, including controlled habitats for plants and animals and medical labora- 

 tory facilities for the study of humans in space. This equipment offered the flexibil- 

 ity necessary for various classes of experiments, such as small, self-contained 

 studies, research using minilabs, and investigations requiring dedicated Spacelab 

 missions. 



The Challenger accident interrupted plans for experimentation using the Shuttle. 

 This suspension was a serious blow to life sciences researchers, many of whom 



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