Marshall Space Flight Center previous Spacelab missions were operated. The advent of the Space Shuttle made possible several major space programs in which MSFC had significant responsibilities. These were the International Space Station, the Hubble Space Telescope, the Chandra X-Ray Observatory, and the Compton Gamma-Ray Observatory. The latter three are part of NASA's series of Great Observatories; this series also includes the Spitzer Space Telescope, but this was not launched by a Space Shuttle and MSFC had no significant role in its development. A manned space station had long been in the plans of visionaries. Wernhar von Braun, in his widely read "Collier's Magazine"
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