The Solar Maximum Mission
satellite
A satellite or artificial satellite is an object intentionally placed into orbit in outer space. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioisotope ...
(or SolarMax) was designed to investigate
Solar phenomena, particularly
solar flares
A solar flare is an intense localized eruption of electromagnetic radiation in the Sun's atmosphere. Flares occur in active regions and are often, but not always, accompanied by coronal mass ejections, solar particle events, and other solar phe ...
. It was launched on February 14, 1980. The SMM was the first satellite based on the
Multimission Modular Spacecraft Multi-mission Modular Spacecraft, also known as the MMS, was originally designed by NASA to serve the largest array of functions for the space program possible to decrease the cost of space missions. It was designed to operate in four distinct are ...
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 Upper Atmosphere Research Satellite (UARS) was a NASA-operated orbital observatory whose mission was to study the Earth's atmosphere, particularly the protective ozone layer. The satellite was deployed from Space Shuttle ''Discovery'' durin ...
.
After an
attitude control
Attitude control is the process of controlling the orientation of an aerospace vehicle with respect to an inertial frame of reference or another entity such as the celestial sphere, certain fields, and nearby objects, etc.
Controlling vehicle ...
failure in Nov 1980 it was put in standby mode until April 1984 when it was repaired by a Shuttle mission.
The Solar Maximum Mission ended on December 2, 1989, when the spacecraft
re-entered the atmosphere and burned up over the Indian Ocean.
[
]
Instruments
Failure and repair
The white-light coronagraph/polarimeter (C/P) took coronal images for about six months from March 1980 before suffering an electronics failure in September that prevented operation.[SOLAR MAXIMUM MISSION (SMM)]
/ref>
In November 1980, the second of four fuses in SMM's attitude control
Attitude control is the process of controlling the orientation of an aerospace vehicle with respect to an inertial frame of reference or another entity such as the celestial sphere, certain fields, and nearby objects, etc.
Controlling vehicle ...
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. SMM was left in standby mode for 3 years.[
The first orbiting, unmanned satellite to be repaired in space, SMM was notable in that its useful life compared with similar ]spacecraft
A spacecraft is a vehicle or machine designed to fly in outer space. A type of artificial satellite, spacecraft are used for a variety of purposes, including communications, Earth observation, meteorology, navigation, space colonization, p ...
was significantly increased by the direct intervention of a manned space mission. During STS-41-C
STS-41-C (formerly STS-13) was NASA's eleventh Space Shuttle mission, and the fifth mission of Space Shuttle ''Challenger''. The launch, which took place on April 6, 1984, marked the first direct ascent trajectory for a Space Shuttle mission. ...
in April 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 Trunnion 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.
This led to an improvised plan which nearly ended the satellite's mission. The improvisation had the astronaut use his hands to grab hold of a solar array and null the rotation by a push from the Maneuvering Unit's thrusters. Instead, this attempt induced higher rates and in multiple axes; the satellite was tumbling out of control and quickly losing battery life. SMM Operations Control Center engineers shut down all non-essential satellite subsystems and with a bit of luck were able to recover the satellite minutes before total failure. The ground support engineers then stabilized the satellite and nulled its rotation rates for capture with the Shuttle's robotic arm. This proved to be a much better plan. The satellite had been fitted with one of the arm's grapple fixture
Grapple fixtures are used on spacecraft or other objects to provide a secure connection for a robotic arm.
North America
The fixtures allowed the Space Shuttle's Canadarm (also known as the Shuttle Remote Manipulator System, or SRMS) to safely g ...
s so that the robotic arm was able to capture and maneuver it into the shuttle's payload bay for repairs.[
During the mission, the SMM's entire attitude control system module and the electronics module for the coronagraph/polarimeter instrument were replaced, and a gas cover was installed over the X-ray polychromator.] Their successful work added five more years to the lifespan of the satellite. The mission was depicted in the 1985 IMAX
IMAX is a proprietary system of high-resolution cameras, film formats, film projectors, and theaters known for having very large screens with a tall aspect ratio (approximately either 1.43:1 or 1.90:1) and steep stadium seating.
Graeme F ...
movie '' The Dream Is Alive''.
Discovery of comets
10 comets were discovered in images from the SMM .
}
, -
, 1988p (SMM-6), , Nov 18, 1988, , O.C. St. Cyr
, -
, 1988q (SMM-7), , Oct 24, 1988, , A. L. Stanger
, -
, 1989m (SMM-8), , Jun 2, 1989 , , O.C. St. Cyr, D. L. Kobe
, -
, 1989q (SMM-9), , Jul 8,1989, , O.C. St. Cyr
, -
, 1989x (SMM-10), , Sep 28,1989 , , O.C. St. Cyr
Findings
Significantly, the SMM's ACRIM instrument package showed that contrary to expectations, the Sun is actually brighter during the sunspot
Sunspots are phenomena on the Sun's photosphere that appear as temporary spots that are darker than the surrounding areas. They are regions of reduced surface temperature caused by concentrations of magnetic flux that inhibit convection. Sun ...
cycle maximum (when the greatest number of dark 'sunspots' appear). This is because sunspots are surrounded by bright features called faculae
A facula (plural: faculae ), Latin for "little torch", is literally a "bright spot". The term has several common technical uses. It is used in planetary nomenclature for naming certain surface features of planets and moons,. and is also a type of ...
, which more than cancel the darkening effect of the sunspot.
The major scientific findings from the SMM are presented in several review articles in a monograph.
End of mission
SMM's orbit slowly decayed due to atmospheric drag taking it down into denser regions.
The March 1989 geomagnetic storm
The March 1989 geomagnetic storm occurred as part of severe to extreme solar storms during early to mid March 1989, the most notable being a geomagnetic storm that struck Earth on March 13. This geomagnetic storm caused a nine-hour outage of Hydr ...
was reported to have led to SMM dropping half a kilometre at the start of the storm and 3 miles over the whole period.[ tp://ftp.ngdc.noaa.gov/STP/SOLAR_DATA/Publications/March1989Events/EffectsoftheMarch1989SolarActivity-Allen%20et%20al%20-%201989.pdf "Effects of the March 1989 Solar Activity" by Allen, Frank, Sauer, Reiff, in ''Eos'', November 14, 1989 p. 1488]
SMM lost attitude control on November 17, 1989, and re-entry and burn-up occurred on 2 December 1989 over the Indian Ocean.[
]
See also
* Advanced Composition Explorer
Advanced Composition Explorer (ACE or Explorer 71) is a NASA Explorer program satellite and space exploration mission to study matter comprising energetic particles from the solar wind, the interplanetary medium, and other sources.
Real-tim ...
* Charles Hyder
* Parker Solar Probe
The Parker Solar Probe (PSP; previously Solar Probe, Solar Probe Plus or Solar Probe+) is a NASA space probe launched in 2018 with the mission of making observations of the outer corona of the Sun. It will approach to within 9.86 solar radii (6 ...
* Solar and Heliospheric Observatory
The Solar and Heliospheric Observatory (SOHO) is a European Space Agency (ESA) spacecraft built by a European industrial consortium led by Matra Marconi Space (now Airbus Defence and Space) that was launched on a Lockheed Martin Atlas IIAS l ...
* WIND (spacecraft)
References
External links
HEASARC
SMM
Marshall Space Flight Center
SMM
Total Solar Irradiance
ACRIM
{{Authority control
Spacecraft launched in 1980
Satellites formerly orbiting Earth
Solar telescopes
Spacecraft launched by Delta rockets
Spacecraft which reentered in 1989
Solar space observatories
NASA satellites orbiting Earth