EURECA, managed by the European Space Agency (ESA), will be launched by 

 the Shuttle and is intended to perform a number of experiments within defined 

 volume, power, and telemetry capabilities. The first EURECA is manifested for 

 deployment in 1990, with retrieval and return to Earth about 6 months later. 

 The experiments for this EURECA have already been selected, but a second 

 EURECA is expected to fly 18 months later, and there are plans to support 

 exobiology experiments with this flight. 



There are thus a wide variety of opportunities in Earth orbit that exobiolo- 

 gists can potentially exploit during the next 15 years using either expendable 

 launch vehicles or the Space Shuttle. The vehicle chosen to carry out any inves- 

 tigation will depend on the services required, the science objectives, and the 

 anticipated funds available. 



In addition to the orbital spacecraft providing permanent or retrievable 

 platforms for exobiology experimentation, a number of telescopes are expected 

 to be launched in the next two decades. Some of these will be free-flyers, and 

 some will be attached to the Space Station or one of its platforms. They will 

 have lifetimes ranging from a few years to decades-depending on the plans for 

 on-orbit servicing. These telescopes will provide facilities for the exobiology 

 community to study the origin and evolution of the biogenic elements and 

 compounds remotely. 



Appendix B presents a compilation of the currently envisioned instrumental 

 capabilities of the various orbital telescopes. The spectral coverage and approxi- 

 mate launch dates are summarized in figure 2-1. It is not yet clear how the 

 Challenger accident or the construction of the Space Station will affect these 

 specific dates, and they should probably be interpreted as giving only the most 

 likely order of launch. Appendix C provides a definition of frequency and wave- 

 length equivalents and Appendix D gives the apparent angular scales of various 

 objects at specified distances; these will be useful for interpreting figure 2-1 and 

 subsequent tables. Table 2-1 enumerates the telescopes being planned by NASA; 

 Table 2-2 lists the ESA telescope projects that have been given approval or 

 strong support in the long-term planning process and which have invited U.S. 

 participation. For every telescope these tables contain, a definition of the mis- 

 sion name or acronym, a tentative launch date, and a description of the current 

 status of the instrumentation is included. Table 2-1 also lists the NASA Center 

 or Research Unit with primary responsibility for the telescope instrumentation. 

 Appendix B provides more detail and describes each of the proposed observing 

 instruments in terms of its frequency or wavelength coverage, the size of the 

 instantaneous field of view that can be imaged, the best spatial resolution that 

 can be achieved, the spectral resolving power, and the limiting sensitivity that 

 can be obtained with modest integration time. Where applicable, the maximum 

 sampling rate and polarization characteristics are also provided. In many 

 instances the data are incomplete because instrument packages have not yet 

 been chosen or outlined. 



