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TIMED mission graphic

Thermosphere, Ionosphere, Mesosphere Energetics and Dynamics

Phase: Operating

Launch Date: December 07, 2001

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Program(s):Heliophysics Research, Solar Terrestrial Probes

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Thermosphere, Ionosphere, Mesosphere Energetics and Dynamics (TIMED)
 explores the Earth's Mesosphere and Lower Thermosphere (60-180 kilometers up), the least explored and understood region of our atmosphere. It is known that the global structure of this region can be perturbed during stratospheric warmings and solar-terrestrial events, but the overall structure and dynamics responses of these effects are not understood. Advances in remote sensing technology employed by TIMED will enable us to explore this region on a global basis from space.


An ultraviolet view of the aurora is superimposed on a city lights image from a weather satellite. The TIMED spacecraft made three passes over the U.S., but after the peak of the storm.

Credit: NASA/APL/Meteorological Satellite Applications Branch, Air Force Weather Agency.

Located between approximately 40-110 miles (60-180 kilometers) above the Earth's surface, the MLTI region is sensitive to external influences from the Sun above and atmospheric layers below it. Its chemical and thermal balance can change rapidly due to naturally-occurring and/or human-induced changes to the energy contained within this region.

The primary science objective of the TIMED mission is to understand the energy transfer into and out of the Mesosphere and Lower Thermosphere/Ionosphere (MLTI) region of the Earth's atmosphere (energetics), as well as the basic structure (i.e., pressure, temperature, and winds) that results from the energy transfer into the region (dynamics).

TIMED is employing advances in remote-sensing technology to globally observe this relatively unexplored frontier from space, making direct measurements of the MLTI region's various energy inputs and outputs and acquiring measurements of its wind, density and temperature profiles. These measurements will provide critical empirical data to help scientists better understand this region's energy balance. The 2-year mission will establish a baseline for future investigations of the MLTI region, providing a basis for early warning of global change.