TERRA is an American (jointly with Japan, and Canada) weather spacecraft that was launched by an Atlas 2AS rocket from Vandenberg AFB at 19:00 UT on 1999 Dec 18. The 4,864-kg spacecraft carries an array of instruments to monitor clouds, aerosals, and solar radiation balance. The CERES (Clouds and Earth's Radiant Energy System) will monitor radiation balance by means of scanning radiometers and bolometers; the MISR (Multi-angle Imaging Spectro-Radiometer) measures reflectance of cloudtops and aerosols, and vegetation in four spectral bands in each of the nine cameras aimed at different angles; the MODIS (MODerate-resolution Imaging Spectro-radiometer) monitors physical and biological processes by means of a scanning spectrometer in 36 spectral bands in visible and infrared wavelengths; the ASTER (Advanced Spacebourne Thermal Emission and Reflection Radiometer) monitors land, oceans, ice and clouds in 14 visible and infrared bands; and MOPITT (Measurement Of Pollution In The Troposphere) monitors carbon dioxide and methane.
Initial parameters of the sun-synchronous orbit were period 98.1 min, apogee 685 km, perigee 654 km, and inclination 98.2 deg.
TERRA and other EOS missions form the core of NASA's Earth Science Enterprise.
The Earth Observing System (EOS) is a science and observation program that will provide long-term (15-year) data sets for Earth system science in order to gain an understanding of the interactions between Earth's land, atmosphere, oceans, and biology. The EOS program is the centerpiece in NASA's Mission to Planet Earth (MTPE). The EOS program was restructured in response to direction from the EOS Engineering Review Committee, U.S. Congress, and the EOS Payload Advisory Panel to fly EOS instruments on intermediate-sized and smaller spacecraft instead of on large space platforms.
Terra (formerly EOS-AM1 is a morning equator-crossing platform which includes a suite of sensors designed to study the diurnal properties of cloud and aerosol radiative fluxes (CERES,MODIS-N, and MISR). Another cluster of instruments on Terra (MODIS-N,MISR, and ASTER) will address issues related to air-land exchanges of energy, carbon, and water. An afternoon (EOS-PM1) spacecraft is planned to complete the study of diurnal radiative fluxes. The complete suite instruments on Terra are ASTER, CERES, MISR, MODIS-N, and MOPITT. TERRA and other EOS missions form the core of NASA's Earth Science Enterprise.
Alternate Names
EOS-1
EOS-AM1
Facts in Brief
Launch Date: 1999-12-18
Launch Vehicle: Atlas-2 AS
Launch Site: Vandenberg AFB, United States
Mass: 4864.0 kg