Last of the Great Observatories to Launch

jqpublic writes "The last in NASA's Great Observatory Program, the Space Infrared Telescope Facility (SIRTF), is set to launch in the wee hours on Monday. The launch can viewed live on NASA's Countdown web site. Interestingly, SIRTF will not be in Earth orbit, but will drift away from Earth by about 15 million kilometers per year. This allows the telescope to cool to very low temperatures (30K), which reduces dramatically the amount of cryogens it needs to carry."