International Satellite for Ionospheric Studies (ISIS)
ISIS-2
- Spacecraft Brief Description - ISIS 2 was an ionospheric observatory instrumented with a sweep- and a fixed-frequency ionosonde, a VLF receiver, energetic and soft particle detectors, an ion mass spectrometer, an electrostatic probe, a retarding potential analyzer, a beacon transmitter, a cosmic noise experiment, and two photometers. Two long crossed-dipole antennas (73 and 18.7 m) were used for the sounding, VLF, and cosmic noise experiments. The spacecraft was spin-stabilized to about 2 rpm after antenna deployment. There were two basic orientation modes for the spacecraft, cartwheel and orbit-aligned. The spacecraft operated approximately the same length of time in each mode, remaining in one mode typically 3 to 5 months. The cartwheel mode with the axis perpendicular to the orbit plane was made available to provide ram and wake data for some experiments for each spin period, rather than for each orbit period. Attitude and spin information was obtained from a three-axis magnetometer and a sun sensor. Control of attitude and spin was possible by means of magnetic torquing. The experiment package also included a programmable tape recorder with a 1-h capacity. For nonrecorded observations, data from satellite and subsatellite regions were telemetered when the spacecraft was in the line of sight of a telemetry station. Telemetry stations were located so that primary data coverage was near the 80-deg-W meridian and near Hawaii, Singapore, Australia, England, France, Norway, India, Japan, Antarctica, New Zealand, and Central Africa. NASA support of the ISIS project was terminated on October 1, 1979. A significant amount of experimental data, however, was acquired after this date by the Canadian project team. ISIS 2 operations were terminated in Canada on March 9, 1984. The Radio Research Laboratories (Tokyo, Japan) then requested and received permission to reactivate ISIS 2. Regular ISIS 2 operations were started from Kashima, Japan, in early August 1984. ISIS 2 was deactivated effective 24, 1990. - Auxiliary Information - Launch Date and Time : 1971-04-01 02:53:00 Epoch Date and Time : 1971-04-02 Apogee (km or AU): 1428. Perigee (km or AU): 1358. Inclination (degree) : 88.1 Orbit Type : Geocentric Information last updated on 1992-03-09 Group: Platform_Details Entry_ID: ISIS-2 Group: Platform_Identification Platform_Category: Earth Observation Satellites Platform_Series_or_Entity: ISIS (International Satellite for Ionospheric S Short_Name: ISIS-2 Long_Name: International Satellite for Ionospheric Studies-2 End_Group Group: Synonymous_Platform_Names Short_Name: ISIS-B End_Group Group: Platform_Associated_Instruments Short_Name: PHOTOMETERS Short_Name: PARTICLE DETECTORS Short_Name: VLF RECEIVERS End_Group Group: Orbit Orbit_Inclination: 88.1 deg Perigee: 1358 km Apogee: 1428 km End_Group Creation_Date: 2007-10-05 Online_Resource: http://nssdc.gsfc.nasa.gov/database/MasterCatalog?sc=1971-024A Group: Platform_Logistics Launch_Date: 1971-04-01 Primary_Sponsor: NASA End_Group End_Group