Synonymous Platform Names:
Geomagnetic Tail Lab
5.15 degrees - 7.45 degrees
43 days - 49 days
47,835 km - 51,024 km
869,421 km - 191,340 km
HEO > Highly Elliptical Orbit
Related Data Sets
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
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:
Cape Canaveral/Kennedy Space Center, USA