Submillimeter Wave Astronomy Satellite (SWAS)
The Submillimeter Wave Astronomy Satellite (SWAS) was an astronomical observatory launched on December 5, 1998 as part of the Small Explorer program within NASA. Investigators at Smithsonian Astrophysical Observatory and Goddard Space Flight Center designed the telescope and the spacecraft, respectively.
The satellite examined microwaves from 487–556 GHz that originated in water molecules, molecular oxygen, atomic carbon, and carbon monoxide in space. This corresponds to wavelengths of about 0.54 to 0.61 millimeters (540 to 610 μm). 
SWAS made observations until July 21, 2004. In June 2005, the spacecraft was reactivated for a 3 month period (after a year of stand-by operation) in order to observe the effects of the Deep Impact probe's collision with comet P/Tempel 1.
The main optic of SWAS is a 55 cm x 71 cm elliptical off-axis Cassegrain telescope, sending light into a pair of Schottky diode receivers.
SWAS observed a unique area of the spectrum alternately described as submillimeter (for the wavelength of light seen), microwave, radio, and/or far infrared.
||540 - 610 μm
||0.55 - 0.7
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