make it safe for display. The OMS and RCS systems used presented the primary dangers due to their toxic hypergolic propellant, and most of their components were permanently removed to prevent any dangerous outgassing. Atlantis is on display at the Kennedy Space Center Visitor Complex, Discovery is at the Udvar-Hazy Center, Endeavour is on display at the California Science Center, and Enterprise is displayed at the Intrepid Sea-Air-Space Museum. Components from the orbiters were transferred to the US Air Force, ISS program, and Russian and Canadian governments. The engines were removed to be used on the Space Launch System, and spare RS-25 nozzles were attached for display purposes. In popular culture The U.S. Postal Service has released several postage issues that depict the Space Shuttle. The first such stamps were issued in 1981, and are on display at the National Postal Museum. See also Notes References External links NSTS 1988 Reference manual How The Space Shuttle Works Orbiter Vehicles The Space Shuttle Era: 1981–2011; interactive multimedia on the Space Shuttle orbiters NASA Human Spaceflight – Shuttle High resolution spherical panoramas over, under, around and through Discovery, Atlantis and Endeavour "No Go-Around: You have only one chance to land the space shuttle" (simulator pilot report, detailed and illustrated), Barry Schiff, April 1999, AOPA Pilot, p. 85., at BarrySchiff.com Aircraft first flown in 1977 American inventions Articles containing video clips Crewed spacecraft Historic American Engineering Record in Texas NASA space launch vehicles Partially reusable space launch vehicles Reusable spaceflight technology Vehicles introduced in 1981