Solar Maximum Mission
Solar Maximum Mission.
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| Mission type | Solar physics |
|---|---|
| Operator | NASA |
| COSPAR ID | 1980-014A |
| SATCAT no. | 11703 |
| Mission duration | 9 years |
| Spacecraft properties | |
| Bus | Multimission Modular Spacecraft |
| Manufacturer | Fairchild Industries |
| Launch mass | 2,315.0 kilograms (5,103.7 lb) |
| Dimensions | ~4 by 2.3 metres (13.1 by 7.5 ft) |
| Start of mission | |
| Launch date | February 14, 1980, 15:57:00 UTC |
| Rocket | Delta 3910 |
| Launch site | Cape Canaveral LC-17A |
| End of mission | |
| Decay date | December 2, 1989 |
| Orbital parameters | |
| Reference system | Geocentric |
| Regime | Low Earth |
| Eccentricity | 0.00029 |
| Perigee | 508.0 kilometers (315.7 mi) |
| Apogee | 512.0 kilometers (318.1 mi) |
| Inclination | 28.5 degrees |
| Period | 94.80 minutes |
| Mean motion | 15.19 |
The Solar Maximum Mission satellite (or SolarMax) was designed to investigate Solar phenomena, particularly solar flares. It was launched on February 14, 1980. The SMM was the first satellite based on the Multimission Modular Spacecraft bus manufactured by Fairchild Industries, a platform which was later used for Landsats 4 and 5 as well as the Upper Atmosphere Research Satellite.
The Solar Maximum Mission ended on December 2, 1989, when the spacecraft re-entered the atmosphere and burned up.
In November 1980, the second of four fuses in SMM's attitude control system failed, causing it to rely on its magnetorquers in order to maintain attitude. In this mode, only three of the seven instruments on board were usable, as the others required the satellite to be accurately pointed at the Sun. The use of the satellite's magnetorquers prevented the satellite from being used in a stable position and caused it to "wobble" around its nominally sun-pointed attitude.
The first orbiting, unmanned satellite to be repaired in space, SMM was notable in that its useful life compared with similar spacecraft was significantly increased by the direct intervention of a manned space mission. During STS-41-C in 1984, the Space Shuttle Challenger rendezvoused with the SMM, astronauts James van Hoften and George Nelson attempted to use the Manned Maneuvering Unit to capture the satellite and to bring it into the orbiter's payload bay for repairs and servicing. The plan was to use an astronaut-piloted Maneuvering Unit to grapple the satellite with the Trunion Pin Attachment Device (TPAD) mounted between the hand controllers of the Maneuvering Unit, null its rotation rates, and allow the Shuttle to bring it into the Shuttle's payload bay for stowage. Three attempts to grapple the satellite using the TPAD failed. The TPAD jaws could not lock onto Solar Max because of an obstructing grommet on the satellite not included in its blueprints.
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