Space Instruments
Desert emissivity and temperature variations in the Namibian Desert are apparent in fine detail from shuttle altitude.

Image courtesy of NASA/GSFC.

ISIR orbit-based terrain
and cloud mapping

The Infrared Spectral Imaging Radiometer (ISIR) is a small, low power, infrared imager that can be used on upcoming weather or remote-sensing satellites. ISIR can obtain high resolution thermal images from space without cooling which eliminates the need for bulky radiation coolers or refrigerators with oscillating pistons. This greatly improves reliability and operating lifetime of future satellite systems, lowers their cost, and simplifies the payload-tosatellite platform interface. Because ISIR does not require a radiation cooler, which must always be pointed at space, it can easily be located anywhere on the spacecraft.

ISIR employs a unique Time Delay and Integration (TDI) technique to significantly increase the radiometric sensitivity of the sensor. This yields enhanced thermal IR terrain and cloud observations through improved resolution, dynamic range and sensitivity.

Improved aircraft contrail detection from the higher quarter kilometer resolution of ISIR was a significant goal of the shuttle experiment in determining potential effects of aviation on climate. Even the shadows of boundary layer clouds were clearly seen, showing the cooling of the surface and enabling scientists to calculate the height of cloud formations.

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