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- The GEOTAIL mission is a collaborative project undertaken by the Institute of Space and Astronautical Science (ISAS) and the National Aeronautics and Space Administration (NASA). Its primary objective is to study the dynamics of the Earth's magnetotail over a wide range of distance, extending from the near-Earth region (8 Earth radii (Re) from the Earth) to the distant tail (about 200 Re). The GEOTAIL spacecraft was designed and built by ISAS and was launched on July 24, 1992. The Geotail mission measures global energy flow and transformation in the magnetotail to increase understanding of fundamental magnetospheric processes. This will include the physics of the magnetopause, the plasma sheet, and reconnection and neutral line formation (i.e., the mechanisms of input, transport, storage, release and conversion of energy in the magnetotail). Geotail, together with Wind, Polar, SOHO, and Cluster projects, constitute a cooperative scientific satellite project designated the International Solar-Terrestrial Physics (ISTP) program which aims at gaining improved understanding of the physics of solar terrestrial relations. Geotail is a spin-stabilized spacecraft utilizing mechanically despun antennas with a design lifetime of about four years. The nominal spin rate of the spacecraft is about 20 rpm around a spin axis maintained between 85 and 89 deg to the ecliptic plane. Geotail is cylindrical, approximately 2.2 m in diameter and 1.6 m high with body-mounted solar cells. Geotail also has a two-hour back-up battery subsystem which operates when the spacecraft is in the Earth's shadow. Real-time telemetry data transmitted in the X-band are received at the Usuda Deep Space Center (UDSC) in Japan. There are two tape recorders on board, each with a capacity of 450 Mbit which allow daily 24-hour data coverage. The data are collected in playback mode by the NASA Deep Space Network (DSN). The Geotail mission is divided into two phases. During the two-year initial phase, the orbit apogee was kept on the nightside of the Earth by using the Moon's gravity in a series of double-lunar swing-by maneuvers that result in the spacecraft spending most of its time in the distant magnetotail (maximum apogee about 200 Earth radii) with a period varying from one to four months. Then, starting in November 1994, there were a series of maneuvers to bring the spacecraft into its near-Earth orbit. This transition orbit lasted about three months with the apogee varying from 50 RE to 30 RE. The second phase is dedicated to the study of near-Earth magnetospheric processes, including neutral line formation. The GEOTAIL mission consists of the following experiments: - Comprehensive Plasma Investigation (CPI) - Electric Fields Detector (EFD) - Energetic Particle and Ion Composition (EPIC) - High-Energy Particles (HEP) - Low-Energy Particles (LEP) - Magnetic Field Experiment - Plasma Waves Investigation (PWI) For more information, see: http://pwg.gsfc.nasa.gov/geotail.shtml Group: Platform_Details Entry_ID: GEOTAIL Group: Platform_Identification Platform_Category: Solar/Space Observation Satellites Short_Name: GEOTAIL End_Group Group: Synonymous_Platform_Names Short_Name: GGS/Geotail Short_Name: GTL Short_Name: Geomagnetic Tail Lab Short_Name: ISTP/Geotail Short_Name: 22049 Short_Name: 1992-044A End_Group Group: Platform_Associated_Instruments Short_Name: MFE Short_Name: PWI Short_Name: LEP Short_Name: HEP Short_Name: EPIC Short_Name: EFD Short_Name: CPI-G End_Group Group: Orbit Orbit_Inclination: 5.15 degrees - 7.45 degrees Period: 43 days - 49 days Perigee: 47,835 km - 51,024 km Apogee: 869,421 km - 191,340 km Orbit_Type: HEO > Highly Elliptical Orbit End_Group Online_Resource: http://pwg.gsfc.nasa.gov/geotail.shtml Online_Resource: http://www.stp.isas.ac.jp/geotail/ Sample_Image: http://nssdc.gsfc.nasa.gov/image/spacecraft/geotail.jpg Group: Platform_Logistics Launch_Date: 1992-07-24 Launch_Site: Cape Canaveral/Kennedy Space Center, USA Primary_Sponsor: ISAS, Japan Primary_Sponsor: NASA End_Group End_Group
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