Space Shuttle design process refurbishment, and the agency studied resupplying the satellite in space. The Air Force planned on having its own fleet of shuttles, and re-built a separate launch facility originally derived from the canceled Manned Orbiting Laboratory program at Vandenberg called Space Launch Complex Six (SLC-6). However, for various reasons, due in large part to the loss of the space shuttle "Challenger" on January 28, 1986, work on SLC-6 was eventually discontinued with no shuttle launches from that location ever taking place. SLC-6 was eventually used for launching the Lockheed Martin-built Athena expendable launch vehicles, which included the successful IKONOS commercial Earth
Space Shuttle Columbia disaster crew of two. Less than a year after the accident, President Bush announced the Vision for Space Exploration, calling for the space shuttle fleet to complete the ISS, with retirement by the year 2010 following the completion of the ISS, to be replaced by a newly developed Crew Exploration Vehicle for travel to the Moon and Mars. NASA planned to return the space shuttle to service around September 2004; that date was pushed back to July 2005. On July 26, 2005, at 10:39 am EST, Space Shuttle "Discovery" cleared the tower on the "Return to Flight" mission STS-114, marking the