Space Shuttle Solid Rocket Booster design or replacing them altogether with liquid "flyback" boosters using either Atlas V or Delta IV EELV technologies. The 5-segment SRB, which would have required little change to the current shuttle infrastructure, would have allowed the space shuttle to carry an additional of payload in an International Space Station-inclination orbit, eliminate the dangerous "Return-to-Launch Site" (RTLS) and "Trans-Oceanic Abort" (TAL) modes, and, by using a so-called "dog-leg maneuver", fly south-to-north polar orbiting flights from Kennedy Space Center. After the destruction of "Columbia", NASA shelved the five-segment SRB for the Shuttle Program, and the three surviving Orbiters, "Discovery", "Atlantis", and "Endeavour"
Space Shuttle Discovery Mercury astronaut John Glenn, who was 77 at the time, flew with "Discovery" on STS-95 in 1998, making him the oldest person to go into space. Had plans to launch United States Department of Defense payloads from Vandenberg Air Force Base gone ahead, "Discovery" would have become the dedicated US Air Force shuttle. Its first West Coast mission, STS-62-A, was scheduled for 1986, but canceled in the aftermath of "Challenger". "Discovery" was retired after completing its final mission, STS 133 on March 9, 2011. The spacecraft is now on display in Virginia at the Steven F. Udvar-Hazy Center, an annex