SIMBAD references

The Submillimeter Wave Astronomy Satellite (SWAS), which was launched in 1998 December, is a NASA mission dedicated to the study of interstellar chemistry and star formation. SWAS is conducting pointed observations of molecular clouds throughout our Galaxy in either the ground state or a low-lying transition of five astrophysically important species: O₂, C I, H₂¹⁸O, ¹³CO, and H₂¹⁶O at approximately 487, 492, 548, 551, and 557 GHz, respectively. The SWAS instrument is comprised of a 54cmx68cm off-axis Cassegrain telescope feeding two independent heterodyne receivers with Schottky barrier diode mixers, passively cooled to about 175 K. An Acousto-Optical Spectrometer (AOS) provides ∼1 MHz (0.6 km/s) frequency resolution and 1400 MHz (840 km/s) total bandwidth with 350 MHz (210 km/s) per line for spectral analysis. SWAS was fully characterized during ground-based testing, and all performance parameters were verified on-orbit. During its on-orbit operation, SWAS observed more than 200 astronomical objects with more than 5000 lines of sight. This paper describes the tests conducted and compares the ground-based test results with the on-orbit test results.