ASTRO 1: NASA 1989 



1 . Spectroscopy (500-3200 A) of planetary atmospheres 



2. Ultraviolet imaging of planets and comets in selected bands 



3. Ultraviolet polarimetry of dust in comets and in interstellar space 



4. Extinction-curve measurements to study size and distribution of interstel- 

 lar grains 



Space Station-Block I: NASA 1995 



1. Dedicated astrometric telescope 



2. Service and instrument changeout on free-flying orbiting telescopes 



3. Construction and servicing of later generations of orbiting telescopes 



Space Infrared Telescope Facility (SIRTF): NASA 1996 

 Infrared Space Observatory (ISO):ESA 1992 



1 . Possible direct imaging of extrasolar planets using superresolution 



2. High-spectral-resolution observations of atoms and molecules in star- 

 forming regions, e.g., water 



3. Continuum and low-resolution observations of dust in star-forming regions 



4. Observations of complex organic molecules 



5. Continuum and low-spectral-resolution studies of grain formation and 

 ejection from stellar atmospheres in the late stages of stellar evolution 



6. Continuum and low-resolution studies of grains in supernovae ejecta 



7. Molecular spectroscopy of solar system planets, satellites, comets, and 

 asteroids 



8. Thermal emission from dust in comets 



9. Reflectance spectroscopy of solid surfaces (asteroids) and ices (comets) 



Far Ultraviolet Spectroscopy Explorer (FUSE): NASA 1996 (Joint with ESA 

 under the name Lyman) 



1. High-resolution, extreme-ultraviolet spectroscopy of the interstellar 

 medium and the intergalactic medium 



Large Deployable Reflector (LDR): NASA 2000 

 Far Infrared Space Telescope (FIRST): ESA 1995 



1 . Direct imaging of extrasolar planets 



2. High-resolution studies of accretion shocks surrounding protostellar nebula 



3. High-spectral-resolution observations of molecules in star-forming regions 



4. Studies of molecular oxygen and water in many transitions in regions of 

 star formation and planets 



In closing, we note that while the next few decades offer exciting opportuni- 

 ties for observational exobiology, even more exciting prospects lie just a little 

 farther in the future. For example, having detected examples of extrasolar 



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