Skip Navigation Links

THE SUN  

Why We Study the Sun  
The Big Questions  
Magnetism - The Key  

SOLAR STRUCTURE  

The Interior  
The Photosphere  
The Chromosphere  
The Transition Region  
The Corona  
The Solar Wind  
The Heliosphere  

SOLAR FEATURES  

Photospheric Features  
Chromospheric Features  
Coronal Features  
Solar Wind Features  

THE SUN IN ACTION  

The Sunspot Cycle  
Solar Flares  
Post Flare Loops  
Coronal Mass Ejections  
Surface and Interior Flows
Helioseismology  

THE MSFC SOLAR GROUP  

The People  
Their Papers  
Their Presentations  

RESEARCH AREAS  

Flare Mechanisms  
3D Magnetic Fields  
The Solar Dynamo  
Solar Cycle Prediction  
Sunspot Database  
Coronal Heating  
Solar Wind Dynamics  

PREVIOUS PROJECTS  

Orbiting Solar Obs.  
Skylab  
Solar Maximum Mission  
SpaceLab 2  
MSSTA  
GOES SXI Instrument  
Yohkoh  

CURRENT PROJECTS  

MSFC Magnetograph  
The Hinode Mission  
The STEREO Mission  
The RHESSI Mission  
The Ulysses Mission  
The GONG Project  
The SOHO Mission  
The TRACE Mission  
The Sun in Time (EPO)  

FUTURE PROJECTS  

The SDO Mission  
Solar Probe  
Interstellar Probe  

The Solar Maximum Mission

SMM_sm.jpg (9510 bytes)

Click on image for larger version.

The Solar Maximum Mission (SMM or SolarMax) was launched on February 14, 1980. It carried several scientific instruments which provided new insights into the nature of solar flares. The spacecraft was rescued and repaired by a 1984 Space Shuttle Challenger mission. This rescue and repair of SMM, (153 kb GIF image) , (124 kb GIF image) , (133 kb GIF image) , extended the useful lifetime of the mission to allow for better coverage of the solar activity cycle. SMM reentered the Earth's atmosphere and burned-up on December 2, 1989.

SMM carried a battery of instruments designed to study solar flares and the active solar atmosphere. These instruments included the Ultraviolet Spectrometer and Polarimeter (UVSP), the Active Cavity Radiometer Irradiance Monitor (ACRIM), the Gamma-Ray Spectrometer (GRS), the Hard X-Ray Burst Spectrometer (HXRBS), the soft X-Ray Polychromator (XRP), the Hard X-ray Imaging Spectrometer (HXIS), and the Coronagraph Polarimeter (CP).

Several members of the MSFC Solar Physics Group were involved with UVSP under the direction of  Dr. Einar Tandberg-Hanssen. UVSP was designed to study the ultraviolet radiation emitted by the Sun in flares, active regions, and prominences. It was capable of acquiring simultaneous images in four different spectral positions as it scanned across the Sun. A rotating polarizer was used to measure magnetic fields as well.

SMM_ACRIM_sm.jpg (27400 bytes)

Click on image for larger version.

The ACRIM instrument package monitored the total energy output of the Sun (often referred to as the "Solar Constant") throughout the mission with great precision. These observation showed the expected dimming of the Sun when sunspots rotated into view and provided important information on the extent of this dimming. More importantly, however, ACRIM showed that the Sun is actually brighter during the maximum of the sunspot cycle when more spots are observed on the Sun's surface. Although the sunspots themselves are dark and produce dimming, they are surrounded by faculae that are bright and, on average, more than offset the dimming due to the sunspots.

The HXIS instrument obtained images over small areas of the sun within six energy bands from 3.5 to 30 keV (3.5 to 0.4Å). The central part of the images had a spatial resolution of 8 arc-seconds. The normal time resolution was about 8 seconds but some flare observations were obtained with 1.5 second time intervals. HXIS observations showed that energetic X-rays are emitted from the footpoints of the magnetic loops seen in solar flares. HXIS showed that large coronal loops with temperatures up to 10 million degrees Kelvin are probably always present in the corona. HXIS also found that X-rays are often seen from widely separated point prior to the onset of a coronal mass ejection.

The GRS instrument had three detector systems that together measured the spectra of flare X-rays and gamma rays with energies from 14keV to 140 MeV. These observations showed that gamma ray emission from even modest flares was fairly common and that particles are accelerated in flares to high energies in just a few seconds.

SMM Web Links

Solar Maximim Mission (GSFC)

Solar Maximim Mission (JPL)

Solar Maximim Mission (NCAR/HAO)

Web Links
NOAA's Space Environment Center - Current Space Weather Conditions Updated Every 5-minutes
SpaceWeather.com - Space Weather Homepage Updated Daily
SolarStorms.org - Learn More About Space Weather and Solar Storms
National Space Weather Program - The U.S. Government and Space Weather
First Gov Image + NASA Privacy, Security, Notices
+ Visit Solar Terrestrial Probes Program
+ Visit Living With a Star Program
NASA Logo Image Author: Dr. David H. Hathaway, david.hathaway @ nasa.gov
Curator: Mitzi Adams, mitzi.adams @ nasa.gov

Last Updated: September 25, 2007