Emerging space flight opportunities in exobiology

Abstract

NASA's Exobiology Program is a mu l t id isc ip l inary and in te rd is c ip l inary research e f fo r t directed toward understanding fundamental questions concerning the or ig in , evolut ion, and d is t r i bu t ion of l i f e and l i f e re la ted molecules throughout the universe. The Exobiology Program includes four major research areas, each encompassing (in a chronological sense) the major epochs associated with the or ig in and evolution of l i f e on a planet: cosmic evolution of biogenic elements and compounds; prebiot ic chemical evolut ion; early evolution of l i f e ; and evolution of advanced l i f e forms. This research strategy involves the synthesis of data collected from so lar system exploration missions, ground-based and orb i t ing observatories, and ground-based and orb i t ing laboratories and is derived from a series of science workshops conducted to evaluate the state of knowledge in each element of exobiological research and to provide recommendations on fu tu re science th rus t s and f l i g h t opportuni t ies. The f i r s t major epoch in the or ig in and evolution of l i f e begins with the nucleosynthesis in stars of the biogenic elements (C,H,N,O,P, S), t h e i r i n t e r a c t i o n w i t h i n the i n t e r s t e l l a r medium, and incorporation into planetoids. Characterizing the processes and understanding the mechanisms by which e x t r a t e r r e s t r i a l organic chemistry occurs w i l l be aided by the use of o rb i t ing telescopes to study chemical evolution processes in developing star systems and in the i n t e r s t e l l a r medium. Space Station simulation experiments w i l l address questions related to the synthesis o f prebiot ic organic compounds in and the ef fect of the i r presence on processes of i n t e r s t e l l a r grain nucleation, aggregation, and condensation. In s i tu sample col lect ion of p r is t ine micrometeorites of cometary, meteor i t ic , or i n t e r s t e l l a r or ig in and the i r subsequent analysis w i l l provide de f in i t i ve information about organic chemical processes during the evo lu t ion of the so lar system. This su i te of s tudies is of fundamental importance in understanding the nature and extent of ex t ra te r res t r i a l organic chemistry. The study of p r e b i o t i c chemistry under vary ing p lanetary conditions focuses on elucidat ing the processes involved in the