Space Telescope Science Institute supports fellows undertaking research associated with all missions within the Cosmic Origins theme: the Herschel Space Observatory, Hubble Space Telescope (HST), James Webb Space Telescope (JWST), Stratospheric Observatory for Infrared Astronomy (SOFIA), and the Spitzer Space Telescope. The research may be theoretical, observational, or instrumental. Each year, since HST's launch in 1990, 8 to 12 fellowships are awarded; from 2009 it hovers about 16. STScI also sponsors a summer student intern program that allows talented undergraduate students from around the world to work with the Institute's scientific staff, providing these students with hands-on experience in state-of-the-art astronomical research. STScI's full-time
Hubble Space Telescope shroud of multi-layer insulation keeps the temperature within the telescope stable and surrounds a light aluminum shell in which the telescope and instruments sit. Within the shell, a graphite-epoxy frame keeps the working parts of the telescope firmly aligned. Because graphite composites are hygroscopic, there was a risk that water vapor absorbed by the truss while in Lockheed's clean room would later be expressed in the vacuum of space; resulting in the telescope's instruments being covered by ice. To reduce that risk, a nitrogen gas purge was performed before launching the telescope into space. While construction of the spacecraft in