Preface 



The Science Workshops on Exobiology in Earth Orbit were held to thor- 

 oughly explore all concepts for scientific experiments of exobiological interest 

 to be carried out on any type of Earth-orbiting spacecraft over the next few 

 decades and to make recommendations on which classes of experiments should 

 be carried out. The Workshops grew out of the realization that many new 

 opportunities would become available to exobiology before the end of this 

 century. Furthermore, three series of workshops redefining the scope of the field 

 of exobiology had just concluded. (The results of these workshops are published 

 in three NASA Special Publications, SP-476, SP-477, and SP-478, listed at the 

 end of Chapter 1.) It was thus an opportune time to connect the basic science 

 objectives defined by these three efforts to the spaceflight missions that were 

 being contemplated for the remainder of this century and that could be used to 

 realize the science objectives. The primary focus was on missions sponsored by 

 the National Aeronautics and Space Administration (NASA) and the European 

 Space Agency (ESA). Necessarily, only those opportunities which were known 

 at the time of the Workshop meetings were considered; subsequent missions 

 were omitted not because of lack of interest, but rather because we were not 

 aware of them. The January 1986 Challenger accident has led to uncertainty in 

 the timetables for the various Earth-orbital missions discussed in this report, and 

 in some cases to the vehicle that will be used to launch them. This must be kept 

 in mind; while the basic scientific objectives and plans described in this report 

 are still valid, the specifics of their implementation are subject to change. 



The Workshops on Exobiology in Earth Orbit should be viewed as the second 

 step of a three-part process, each step of which increases the number of people 

 who are thinking about the role of Earth-orbital space missions in the field of 

 exobiology. The first step was a series of informal meetings held at NASA's 

 Ames Research Center during 1982-83 that included primarily Ames investiga- 

 tors. The Workshops on Exobiology in Earth Orbit, the second step of the 

 process, was composed of about 40 scientists from around the world, including 

 astronomers, chemists, biologists, and geologists; the recommendations for 

 experiments, summarized in Chapter 6, represent the consensus opinion of this 

 particular group of experts. The third step in the process begins with the distri- 

 bution of this report. All interested scientists can now consider the classes of 



VII 



