SWAS, the Submillimeter Wave Astronomy Satellite, had a 0.6m telescope with a 490 to 550 GHz submillimeter receiver and an acousto-optical spectrometer. SWAS was used to study the cooling of molecular cloud cores, the sites of star formation in the Milky Way galaxy, by measuring lines from molecular oxygen and water.

Typical orbit: 644 km circular orbit, 69.9 deg inclination.

• 1998 December 6 - SWAS - Program: Small Explorer. Launch Site: Point Arguello WADZ. Launch Complex: -. Launch Vehicle: Pegasus. Perigee: 637 km (395 mi). Apogee: 651 km (404 mi). Inclination: 69.90 deg.
  On December 3 the Orbital Sciences L-1011 Stargazer took off from Vandenberg AFB Runway 30/12 carrying a Pegasus XL launch vehicle with the SWAS satellite aboard. It reached the drop box at 36.0N 123.0W over the Pacific, but due to a software-related problem the range ordered the launch scrubbed and the L-1011 returned to base. After a further delay due to weather, the L-1011 took off at 23:58 GMT on December 5 and SWAS reached orbit and separated from the third stage at 01:09 GMT. SWAS, the Sub-millimetre Wave Astronomy Satellite, had a 0.6m telescope with a 490 to 550 GHz sub-millimetre receiver and an acousto-optical spectrometer. SWAS was used to study the cooling of molecular cloud cores, the sites of star formation in our galaxy, by measuring lines from molecular oxygen and water.