Magsat
Magsat
|
|
| Mission type | Earth observation |
|---|---|
| Operator | NASA / USGS |
| COSPAR ID | 1979-094A |
| SATCAT no. | 11604 |
| Mission duration | 8 months |
| Spacecraft properties | |
| Launch mass | 158.0 kilograms (348.3 lb) |
| Start of mission | |
| Launch date | 30 October 1979, 14:16 UTC |
| Rocket | Scout G-1 S203C |
| Launch site | Vandenberg SLC-5 |
| End of mission | |
| Decay date | 11 June 1980 |
| Orbital parameters | |
| Reference system | Geocentric |
| Regime | LEO |
| Eccentricity | 0.0005741 |
| Perigee | 351.9 kilometers (218.7 mi) |
| Apogee | 578.4 kilometers (359.4 mi) |
| Inclination | 96.7488° |
| Period | 93.90 minutes |
| RAAN | 162.3717 degrees |
| Argument of perigee | 301.4198 degrees |
| Mean anomaly | 59.7851 degrees |
| Mean motion | 16.40347862 |
| Epoch | 11 June 1980, 02:25:27 UTC |
| Revolution no. | 3497 |
Magsat (Magnetic Field Satellite, Explorer 61, Applications Explorer Mission-3 or AEM-3) spacecraft was launched in the fall of 1979 and ended in the spring of 1980. The mission was to map the Earth's magnetic field, the satellite had two magnetometers. The scalar (Cesium vapor) and vector (fluxgate) magnetometers gave Magsat a capability beyond that of any previous spacecraft. Extended by a telescoping boom, the magnetometers were distanced from the magnetic field created by the satellite and its electronics. The satellite carried two magnetometers, a three-axis fluxgate magnetometer for determining the strength and direction of magnetic fields, and an ion-vapor/vector magnetometer for determining the magnetic field caused by the vector magnetometer itself. MAGSAT is considered to be one of the more important Science/Earth orbiting satellites launched; the data it accumulated is still being used, particularly in linking new satellite data to past observations.
After launch the payload was brought to an orbit of 96.8° facing the Sun as the Earth rotated underneath. It was kept in a close Earth orbit, with vector magnetometers capable of sensing magnetic fields closer to Earth's surface. The data collected by this satellite allowed a 3D-mapping of the Earth's magnetic interior as never seen before. In combination with a later satellite, Ørsted, it has been an essential component for explaining the current declining state of the Earth's magnetic field.
On October 30, 1979 Magsat was launched from pad SLC-5 at Vandenberg AFB in California on a Scout II (101) rocket bearing 97° in a dusk to dawn orbit. The spacecraft was placed in an orbit with a perigee of 350 kilometres (220 mi) and an apogee of 550 kilometres (340 mi). After reaching orbit, its telescoping boom was extended outward by 6 metres (20 ft). Two star cameras were used to define the position of the spacecraft relative to Earth. The orbit allowed the satellite to map a majority of the Earth's surfaces except the geographic poles. The satellite decayed from orbit on June 11, 1980.
According to a Johns Hopkins University / Applied Physics Laboratory (JHU/APL) report, and archival NASA source documentation (Johns Hopkins APL Technical Digest, July–September 1980, Vol. 1, No. 3), the MAGSAT spacecraft utilized two RCA 1802 microprocessors running at a 2 MHz clock speed in a redundant setup. A stored memory of 2.8 kilobytes in PROMs with 1 K bytes of random access memory (RAM) provided the program and working space for the microprocessor. Other integrated circuits chips of the CDP 1800 family of circuits were also used, including the CDP 1852 interface circuit and the CDP 1822 1K x 1 RAM, as well as Harris CMOS 6611A PROMS.
...
Wikipedia