Submillimeter Wave Astronomy Satellite

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.

Comparison
Name	Year	Wavelength	Aperture
Human Eye	-	0.39-0.75 μm	0.01 m
SWAS	1998	540 - 610 μm	0.55 - 0.7
Spitzer	2003	3-180 μm	0.85 m
Hubble WFC3	2009	0.2-1.7 μm	2.4 m
Herschel	2009	60-672 μm	3.5 m

See also

• Far infrared astronomy
• Submillimeter astronomy

External links

• SWAS homepage at Harvard
• IRSA - SWAS at Caltech
• Small Explorer project: Submillimeter Wave Astronomy Satellite (SWAS). Mission operations and data analysis plan
• A 550 GHZ NEAR-FIELD ANTENNA MEASUREMENT SYSTEM FOR SWAS (1994)