International Space Station program out of 28 flights have not been to the ISS, and only the planned Hubble Space Telescope servicing mission in 2009 will not be ISS-related out of 13 planned missions until the end of the Space Shuttle program in 2010). The Space Shuttle was retired from service upon the conclusion of Atlantis' final flight on July 21, 2011. NASA was reliant even at the time on some of the resupply contracts being fielded out to Soyuz and Progress and the other unmanned tugs, but it had launched a few years earlier into a program of aggressive development of commercial US
Spitzer Space Telescope observe the stars at noon. Previous space observatories (such as IRAS, the Infrared Astronomical Satellite, and ISO, the Infrared Space Observatory) were launched during the 1980s and 1990s and great advances in astronomical technology have been made since then. Most of the early concepts envisioned repeated flights aboard the NASA Space Shuttle. This approach was developed in an era when the Shuttle program was expected to support weekly flights of up to 30 days duration. A May 1983 NASA proposal described SIRTF as a Shuttle-attached mission, with an evolving scientific instrument payload. Several flights were anticipated with a probable transition