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TIMED in Low Earth orbit.
Mission type Ionosphere
Atmospheric science
Space weather research.
Operator NASA
COSPAR ID 2001-055B
SATCAT № 26998
Website TIMED at APL
Mission duration 2 years (planned)
8+ years (ongoing)
Spacecraft properties
Manufacturer Applied Physics Laboratory
Launch mass 660 kilograms (1,460 lb)
Power 300 W (nominal)
Start of mission
Launch date 7 December 2001, 15:07:35 (2001-12-07UTC15:07:35Z) UTC
Rocket Delta II 7920-10 D289
Launch site Vandenberg SLC-2W
Orbital parameters
Reference system Geocentric
Regime Low Earth
Semi-major axis 6,983.0 kilometers (4,339.0 mi)
Eccentricity 0.0000651
Perigee 611.7 kilometers (380.1 mi)
Apogee 612.6 kilometers (380.7 mi)
Inclination 74.0722º
Period 96.8 minutes
RAAN 302.7819 degrees
Argument of perigee 343.2534 degrees
Mean anomaly 16.86255 degrees
Mean motion 14.87734465
Epoch 26 June 2016
Revolution number 78858

The TIMED (Thermosphere Ionosphere Mesosphere Energetics and Dynamics) is an orbiter mission dedicated 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 mission has been extended several times, and has now collected data over an entire solar cycle, which helps in its goal to differentiate the Sun's effects on the atmosphere from other effects.[1]

Atmospheric region under study[edit]

TIMED Mission diagram (NASA)

The Mesosphere and Lower Thermosphere (MLT) region of the atmosphere to be studied by TIMED is located between 60–180 km 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.

Scientific instruments onboard[edit]

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[edit]

  • Mass: 660 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 [clarification needed]
  • Data Downlink: 4 megabits per second
  • Memory: 5 gigabits
  • Control & Data Handling Processor: Mongoose-V
  • Attitude:
    • Control - Within 0.5 degrees
    • Knowledge - Within 0.03 degrees
    • Processor: RTX2010
  • Total Mission Cost:
    • Spacecraft: $195 million
    • Ground Operations: $42 million

Instrument Teams[edit]

United States[edit]


See also[edit]


External links[edit]