The TIMED (Thermosphere Ionosphere Mesosphere Energetics and Dynamics) mission is a two year project to study the dynamics of the Mesosphere and Lower Thermosphere (MLT) portion of the Earth's atmosphere. The mission was launched from Vandenberg Air Force Base in California on December 7, 2001 aboard a Delta II rocket launch vehicle. The project is sponsored and managed by NASA, while the spacecraft was designed and assembled by the Applied Physics Laboratory at Johns Hopkins University.

The TIMED spacecraft (NASA GSFC)

TIMED Mission diagram (NASA)

The MLT Region of the Atmosphere

Layers of Atmosphere (NOAA)

The MLT region of the atmosphere to be studied by TIMED is located between 60-180km above the Earth's surface where energy from solar radiation is first deposited into the atmosphere. This can have profound effects on Earth's upper atmospheric regions, particularly during the peak of the sun's 11-year solar cycle when the greatest amounts of its energy are being released. Understanding these interactions is also important for our understanding of various subjects in geophysics, meteorology, and atmospheric science, as solar radiation is one of the primary driving forces behind atmospheric tides. Changes in the MLT can also affect modern satellite and radio telecommunications.

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Scientific instruments onboard

The spacecraft payload consists of the following four main instruments:

Global Ultraviolet Imager (GUVI)

A spatial-scanning, far-ultraviolet spectrograph designed to globally measure the composition and temperature profiles of the MLT region, as well as its auroral energy inputs.

Solar Extreme Ultraviolet Experiment (SEE)

A spectrometer and a suite of photometers designed to measure the solar soft X-rays, extreme-ultraviolet and far-ultraviolet radiation that is deposited into the MLT region.

TIMED Doppler Interferometer (TIDI)

Designed to globally measure the wind and temperature profiles of the MLT region.

Sounding of the Atmosphere using Broadband Emission Radiometry (SABER)

Multichannel radiometer designed to measure heat emitted by the atmosphere over a broad altitude and spectral range, as well as global temperature profiles and sources of atmospheric cooling.

Spacecraft stats

• Mass: 587 kilograms
• Dimensions:
  • 2.72 meters high
  • 1.61 meters wide (launch configuration)
  • 11.73 meters wide (solar arrays deployed)
  • 1.2 meters deep
• Power Consumption: 406 watts per orbit
• Data Downlink: 4 megabits per second
• Memory: 5 gigabits
• Attitude:
  • Control - Within 0.5 degrees
  • Knowledge - Within 0.03 degrees
• Total Mission Cost:
  • Spacecraft: $195 million
  • Ground Operations: $42 millions

Instrument Teams

• University of Alaska, Fairbanks, Alaska
• University of California, Berkeley, California
• Jet Propulsion Laboratory, Pasadena, California
• CREES-York University, Toronto, Canada
• University of Colorado, Boulder, Colorado
• National Center for Atmospheric Research, Boulder, Colorado
• National Oceanic and Atmospheric Administration, Boulder, Colorado
• British Antarctic Survey, Cambridge, England
• Rostock University, Rostock, Germany
• The Johns Hopkins University, Laurel, Maryland
• Air Force Research Laboratory, Hanscom Air Force Base, Massachusetts
• Stewart Radiance Laboratory, Bedford, Massachusetts
• University of Michigan, Ann Arbor, Michigan
• Astrophysical Institute of Andalucia (IAA), Granada, Spain
• Southwest Research Institute, San Antonio, Texas
• Hovemere Limited, Kent, U.K.
• Utah State University, Logan, Utah
• Computational Physics, Inc., Fairfax, Virginia
• Hampton University, Hampton, Virgina
• NASA Langley Research Center, Hampton, Virginia
• G&A Technical Software Inc., Hampton, Virginia
• Naval Research Laboratory, Washington, D.C.

Related Articles

• Upper Atmosphere Research Satellite

External Links

TIMED mission page at NASA GSFC (http://stp.gsfc.nasa.gov/missions/timed/timed.htm)