Science and applications of He-II in spaceApplications of He II in space environment are described, with special attention given to application of He II as a cryogen in several completed and planned space mission. Major applications of He II include the completed Infrared Astronomical Satellite and the Spacelab 2 Infrared Telescope missions, and planned missions that include the NASA Cosmic Background Experiment, the Space IR Telescope, the Large Deployable Reflector, and the ESA's Infrared Space Observatory. Science experiments include the completed Superfluid Helium in Zero Gravity Experiment and the planned Superfluid Helium On-Orbit Transfer and Lambda Point experiments.