The Solar Maximum Mission (SMM) was designed to provide coordinated
observations of solar activity, in particular solar flares, during a
period of maximum solar activity. The payload was made up of
... seven
instruments, specifically selected to study the short-wavelength and
coronal manifestations of flares. The total solar irradiance was
measured by ACRIM, gamma rays by GRS, hard X-rays by the HXRBS, soft
X-rays by XRP and HXIS, ultraviolet by UVSP, and the C/P imaged the
corona 2-5 radii from the sun. Data were obtained on the storage and
release of flare energy, particle acceleration, formation of hot
plasma, and mass ejection. Complementary studies were made as part of
the SMM guest investigator program, and coordinated in-situ
measurements of flare particle emissions were made from the ISEE-3
spacecraft.
The SMM observatory was of modular construction and measured
approximately 4 m in length, fitting into a circular envelope 2.3 m in
diameter. The instrument module occupied the top 2.3 m and contained
all the solar payload instruments together with the fine-pointing
Sun-sensor system. Below the instrument module was the Multimission
Modular Spacecraft (MMS) containing the systems for attitude control,
power, communication, and data handling. Between the instrument module
and the MMS was the transition adaptor, supporting two fixed solar
paddles that supplied between 1500 and 3000 W of power.
Quick and coordinated responses to solar flares were considered
essential for meeting the scientific objectives of the
mission. Therefore, the ground system was designed to facilitate
coordinated data evaluation, observation, planning, and command uplink
to the onboard stored command processor. Onboard coordination of
response to a flare was performed in real time. The attitude-control
software allowed observatory repointings and slow scanning motions;
there was also a special module for tracking a solar feature over many
days.
A repair mission by the space shuttle (STS-41C) was performed in
1984. During the repair mission the Shuttle astronauts rendezvoused
with SMM and replaced successfully some hardware. As a result the
coronagraph observations resumed until the end of mission.
SMM collected data until Nov. 24, 1989, and re-entered on Dec. 2, 1989.
For more details, see
E. G. Chipman, Ap. J., v. 244, p. L113, 1981,
and J. D. Bohlin et al., Solar Phys., v. 65, p. 5,1980.
LAUNCH DATE- 02/14/80
ORBIT PARAMETERS
ORBIT TYPE- GEOCENTRIC EPOCH DATE- 02/15/80
ORBIT PERIOD- 94.8 MIN INCLINATION- 28.5 DEG
PERIAPSIS- 508. KM ALT APOAPSIS- 512. KM ALT 
