Space Science in the Twenty-First Century: Imperatives for the Decades 1995 to 2015 -- Copyright -- Preface -- Contents -- 1 Introduction -- 2 Earth Sciences: A Mission to Planet Earth -- BACKGROUND -- EARTH AS A GLOBAL SYSTEM -- SCIENTIFIC THEMES -- RECOMMENDED PROGRAM: POST-1995 -- THE ROLE OF NASA IN EARTH SCIENCES -- NATIONAL COORDINATION -- CONCLUSIONS -- 3 Planetary and Lunar Exploration -- BACKGROUND -- GOALS OF PLANETARY EXPLORATION -- ACHIEVEMENTS OF PLANETARY EXPLORATION -- FUTURE PLANETARY EXPLORATION-A BALANCED PLANETARY PROGRAM -- Prospective Pre-1995 Missions -- Recommended Program: Post-1995 -- Terrestrial Planets -- Recommended Missions -- Outer Planets and Satellites -- Recommended Missions -- Primitive Bodies -- Recommended Missions -- Other Planetary Systems -- Recommended Missions -- A Mars Focus -- Recommended Missions -- CONCLUSION -- 4 Solar System Space Physics -- BACKGROUND -- THE SUN, SOLAR PROCESSES, AND VARIABILITY -- THE SUN-EARTH SYSTEM, THE MAGNETOSPHERE, AND THE AURORA -- THE UPPER ATMOSPHERE -- MAGNETOSPHERES OF OTHER PLANETS AND COMETS -- CONNECTIONS OF SOLAR SYSTEM SPACE PHYSICS TO LABORATORY AND ASTROPHYSICAL PLASMAS -- NATURE OF THE FIELD -- CURRENT FLIGHT PROJECTS -- PROSPECTIVE PRE-1995 MISSIONS -- RECOMMENDED PROGRAM: POST-1995 -- CONCLUSIONS -- 5 Astronomy and Astrophysics -- BACKGROUND -- MAJOR SCIENTIFIC QUESTIONS -- THE EVOLUTION OF SPACE ASTRONOMY -- RECOMMENDED PROGRAM: POST-1995 -- Imaging Interferometer (Optical and Infrared) -- The Large Deployable Reflector (LDR) -- An 8-to 16-m Telescope for Ultraviolet, Optical, and Infrared Wavelengths -- X-Ray Instruments of Large Area and Throughput -- Gamma-Ray Telescopes -- Cosmic-Ray Research -- CROSS-LINKS WITH OTHER DISCIPLINES -- CONCLUSIONS -- 6 Fundamental Physics and Chemistry: Relativistic Gravitation and Microgravity Science -- OVERVIEW.

A. RELATIVISTIC GRAVITATION -- Background -- Tests of General Relativity Theory in Weak Fields -- Deflection of Light -- Gravitational Red Shift -- Relativistic Frame Dragging -- Principle of Equivalence -- Secular Change in the Gravitational Constant -- Gravitational Waves -- Pre-1995 Program for Relativistic Gravitation -- Recommended Program for Relativistic Gravitation: Post-1995 -- B. MICROGRAVITY SCIENCE -- Background -- Observation of States in Equilibrium -- Observation of States Destroyed by Gravity -- States Far From Equilibrium -- Conclusions and Recommendations for Microgravity Science -- 7 Life Sciences -- BACKGROUND -- LIFE SCIENCE GOALS AND MAJOR QUESTIONS -- Exobiology Goals -- Major Questions for Exobiology: 1995 to 2015 -- Global Biology Goals -- Major Questions for Global Biology: 1995 to 2015 -- Space Biology Goals -- Major Questions for Space Biology: 1995 to 2015 -- Space Medicine Goal -- Major Questions for Space Medicine: 1995 to 2015 -- RECOMMENDED PROGRAM: POST-1995 -- Recommendations for Exobiology -- Recommendations for Global Biology -- Recommendations for Space Biology and Space Medicine -- Significance of Recommendations -- 8 Interdisciplinary Studies -- 9 Human Presence in Space -- SPACE AGE SCIENCE -- THE SCOPE OF HUMAN PRESENCE IN SPACE -- 10 International Cooperation -- 11 Preconditions and Infrastructure.