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Observation Data |
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The EOS program is an international cooperative project initiated by NASA that contributes to the resolution of global environmental issues.
The EOS program was started in the 1980's. An Announcement of Opportunity (AO) for instruments and Science Teams associated with those instruments, was issued, and 30 instruments and Science Teams were selected in 1988, as well as 29 interdisciplinary research themes. ITIR proposed by MITI, was also selected at this time.
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A main characteristic of this EOS program is that an Investigators Working Group (IWG), composed of Principal Investigators (PIs) of the interdisciplinary research teams and PIs and researchers of each instrument team, establishes the scientific purposes of EOS. Moreover, the IWG has been playing a leading role by making recommendations to NASA about the design and implementation of the program, as EOS was being developed. |
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The EOS program can be divided into the following three parts: |
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| EOS Science; |
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| Observation System of EOS (Spacecraft, Sensors); |
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| EOSDIS (EOS Data and Information System). |
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The EOS Science targets the elucidation of global climate change, and investigations of global climate change phenomena. It supports investigations of the observed water circulation, energy cycle, ocean, the chemistry of the troposphere and the lower stratosphere, land-water ecosystem, glaciers and polar ice, chemistries of the middle and upper stratosphere, and the earth itself.
After several reviews, the spacecraft for EOS consist of nine medium spacecraft and five small spacecraft. The number of the sensors was reduced from an initial number of 30, to 24 (including ASTER). Since the EOS Program aims at a long-term, continuous observation for 15 years, the observation lifetime for each spacecraft is planned to be six years long.
EOSDIS (EOS Data and Information System) controls the spacecraft and sensors, receives observation requests from users, makes the observation plans, and processes, archives, and distributes the data.
The EOSDIS interface is standardized, and facilitates easy insertion of advanced technologies during the operation period; and can be updated at the component level. It is constructed as a system which has a physical distribution function, with logical integration. |
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In spite of the frequent reviews and the reduction of the program (related to the reduction of the budget), the development of the sensors, the development of the algorithms to obtain the higher level processed products from the observation data, and the development of EOSDIS are actively being implemented for the launch of the first platform ( TERRA) in 1999, and for the follow-on data use.
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Overview |
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TERRA is the earth observing satellite that launched in 1999 as the first spacecraft of a large scale Earth Observation Program that NASA (National Aeronautics and Space Administration) promotes. TERRA was recently renamed, and was formerly known as EOS-AM1. It is an international cooperative program where NASA provides CERES, MODIS, and MISR in addition to the satellite bus; Japan provides ASTER, and Canada provides MOPITT. The TERRA launch site is The Western Test Range of the U.S. Air Force. The mission period is six years.
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Observation and Research Objectives |
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Clouds, Aerosols and Radiation Balance
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Land Characteristics
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Carbon Cycle
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In addition to ASTER, this satellite is planned to be equipped with the following instruments: |
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| CERES (Clouds and the Earth's Radiant Energy System) |
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| MISR (Multi-angle Imaging Spectro Radiometer) |
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| MODIS (MODerate-resolution Imaging Spectro radiometer) |
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| MOPITT (Measurements of Pollution in the Troposphere) |
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The data acquired by each sensor is stored on the data recorder, and received at the ground station in White Sands, New Mexico, U.S.A. via the Tracking and Data Relay Satellite System (TDRSS). |
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Orbit Parameters and the Major Specification of TERRA |
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| Orbit |
Sun-Synchronous , Polar Orbit |
| Equatorial Time |
Descending Node at 10:30 a.m. |
| Eccentricity |
0.0012 |
| Semi-major axis (Mean) |
707.8 km |
| Altitude range |
700-737 km |
| Inclination |
98.2degrees |
| Recurrence Cycle |
16 days at the Equator |
| Distance between adjacent orbits |
172km |
| Orbital Period |
98.88 Minutes |
| Orbit Determination Accuracy |
150m(3 sigma) |
| Repetition accuracy |
<20 km. 3 sigma |
| Mission Period |
6 Years |
| Observation Instruments |
Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER)
Clouds and the Earth's Radiant Energy System (CERES)
Multi- angle Imaging Spectro Radiometer (MISR)
Moderate Resolution Imaging Spectroradiometer (MODIS)
Measurements of Pollution in the Troposphere (MOPITT) |
| Major Specifications |
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| Pointing Accuracy |
150 Arcsec(3 sigma) |
| Pointing Determination Accuracy |
90 Arcsec(3 sigma) |
| Dimensions (Stowed) |
Approximately 6.8 m long x 3.2m diameter |
| Satellite Weight |
Maximum 5,040 kg |
| Payload Weight |
1,155 kg |
| Electric Power for Satellite |
Average 2.5KW and Maximum 3.5KW |
| Average Electric Power for Payoad |
1,195W |
| Communication |
Ku-band 150Mbps (science data)
X-band 13Mbps (DB), 105Mbps (DDL)
S-band 16Kbps (telemetry) and 10Kbps (command) |
Observation Data acquired by TERRA will be transmitted to the NASA Ground Stations via the Tracking and Data Relay Satellite System (TDRSS). These data are forwarded to Goddard Space Flight Center (GSFC) in Maryland where the depacketization and the extraction of the original observation data are performed. ASTER data is stored on D3 cassette tapes and airmailed from GSFC to ERSDAC on a daily basis. Image data is directly transmitted to NASA Polar Ground Stations from TERRA after the year 2000, and TDRSS will no longer be used. It is planned to receive the ASTER image data of Japan at a domestic station in real time when TERRA flies over Japan.
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Copyright (c) 2000-2010 Earth Remote Sensing Data Analysis Center (ERSDAC)
All rights reserved.
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