Space Science in the Twenty-First Century: Imperatives for the Decades 1995 to 2015 -- Copyright -- Foreword -- Preface -- Contents -- 1 Design and Implications of a Research Mission to Planet Earth -- INTRODUCTION -- GRAND THEMES -- MEASUREMENT STRATEGY -- SYSTEMS OVERVIEW -- 1. A Satellite-based Observing System -- 2. Complementary In Situ Observing Systems -- 3. Modeling -- 4. Data System -- STRATEGY OVERVIEW -- 2 Earth Sciences-Status of Understanding -- INTRODUCTION -- THE EARTH'S INTERIOR AND CRUST -- Plate Tectonics -- Gravitational and Magnetic Fields -- Structure of the Earth's Interior -- History of Earth's Crust -- THE EARTH'S AIR AND WATER -- Atmosphere -- Oceans -- Fresh Water and Ice -- The Challenge: Climate Prediction -- LIFE ON EARTH -- Relation of Physical and Biological Earth History -- Global Biota: Revelations from Space -- Biogeochemical Cycles -- The Carbon Cycle -- The Nitrogen Cycle -- The Phosphorus Cycle -- The Sulfur Cycle -- Human Activities -- PLANET EARTH IN THE SOLAR SYSTEM -- 3 The Earth as a System-A Global Perspective for Future Planning -- INTRODUCTION-OBJECTIVES AND GRAND THEMES -- GRAND THEME 1: STRUCTURE, EVOLUTION, AND DYNAMICS OF THE EARTH'S INTERIOR AND CRUST -- Global Issues -- The Measurements Required -- Structure and Chemistry -- Dynamics -- Geological Mapping -- Global Topography -- Surface Imaging and Sounding -- GRAND THEME 2: ATMOSPHERE, OCEANS, CRYOSPHERE, AND HYDROLOGIC CYCLE -- Global Issues -- The Measurements Required -- GRAND THEME 3: LIVING ORGANISMS AND THEIR INTERACTION WITH THE ENVIRONMENT -- Global Issues -- The Measurements Required -- GRAND THEME 4: INTERACTION OF HUMAN ACTIVITIES WITH THE NATURAL ENVIRONMENT -- Global Issues -- The Measurements Required -- Human Impact -- Hazards -- 4 Current and Planned Earth Observing Satellite Missions: 1986 to 1995 -- INTRODUCTION.

CURRENT PROGRAMS -- Land Observing Systems -- Landsat -- Systeme Probatoire d'Observation de la Terre (SPOT) -- Shuttle Imaging Radar (SIR) -- Ocean Observing Systems -- Atmosphere Observing Systems -- Earth's Radiation Budget -- Atmospheric Chemistry -- Geodynamics -- POTENTIAL INITIATIVES: 1986 TO 1995 -- Upper Atmosphere Research Satellite (UARS) -- Scatterometer -- Ocean Topography Experiment for Ocean Circulation (TOPEX)/Poseidon -- Ocean Color Imager -- Shuttle-Spacelab Payloads -- Tethered Satellite System -- Magnetic Field Satellite -- Geopotential Research Mission (GRM) -- Earth Observing System (EOS) -- COMPUTERS, COMMUNICATIONS, AND DATA MANAGEMENT -- 5 Elements of the Mission to Planet Earth -- SYSTEMS DEFINITION -- ELEMENTS OF THE SYSTEM -- Satellite "Earth Observing System" (EOS) -- Smart Ground Stations -- Seismic Measurements -- Geodetic Measurements -- Meteorological and Hydrological Measurements -- Measurement of Soil Properties -- Simple Ground Installations -- Magnetic Field -- Ocean Bottom Stations -- Moored Buoys -- Floating Buoys -- Ships: Research and Voluntary Observing -- Global Geodetic Observations at the Centimeter Level -- The Plato System -- DATA MANAGEMENT AND ANALYSIS -- INTEGRATION OF RESULTS FROM OBSERVING SYSTEMS -- 6 Science Policy Considerations and Recommendations -- INTRODUCTION -- RECOMMENDATIONS -- 1. National Coordination of Agency Roles -- 2. International Coordination and Cooperation -- 3. NASA's Role in the Solid Earth Sciences -- Appendix A EOS Instrument Descriptions.