[1] The telescope was designed by the Smithsonian Astrophysical Observatory (SAO) and integrated by Ball Aerospace, while the spacecraft was built by NASA's Goddard Space Flight Center (GSFC).

The project began with the Mission Definition Phase, officially starting on 29 September 1989, and running through 31 January 1992.

During this time, the mission underwent a conceptual design review on 8 June 1990, and a demonstration of the Schottky receivers and acousto-optical spectrometer concept was performed on 8 November 1991.

[3] SWAS was designed to study the chemical composition, energy balance and structure of interstellar clouds, both galactic and extragalactic, and investigate the processes of stellar and planetary formation.

The telescope is composed of three main components: a 55 × 71 cm (22 × 28 in) elliptical off-axis Cassegrain reflector with a beam width of 4 arcminutes at operating frequencies,[1][4] two Schottky diode receivers, and an acousto-optical spectrometer.

[1][2] Detailed 1° x 1° maps of giant molecular and dark cloud cores are generated from a grid of measurements taken at 3.7 arcminutes spacings.

Outputs of the two SWAS receivers are combined to form a final intermediate frequency, which extends from 1.4 to 2.8 GHz and is dispersed into 1400 1-MHz channels by the AOS.

The SWAS measurements will provide new information about the physical conditions (density and temperature) and chemistry in star-forming molecular clouds.

[6] The spacecraft was delivered to Orbital Sciences Corporation at Vandenberg Air Force Base on 2 November 1998, for integration onto their Pegasus XL launch vehicle.