The commissioning phase of the mission lasted until December 19, 1998, when the telescope began producing useful science data. The SWAS mission had a planned duration of two years and a cost estimate of , but mission extensions allowed for five and a half years of continuous science operations. During this time, data was taken on more than 200 astronomical objects. The decision was made to end science and spacecraft operations on July 21, 2004, at which time the spacecraft was placed into hibernation.