The Space Shuttle Discovery is set to roll out to the launch pad at Kennedy Space Center on Tuesday, June 14. With an upgraded external fuel tank that includes heaters to prevent ice from forming in areas that could pose a danger to the shuttle during lift off, NASA is preparing another attempt for Return To Flight, the first Shuttle mission since the Columbia disaster. The previously scheduled flight in May was scrubbed when unexpected amounts of ice formed on tubes that deliver the cryogenic fuel to the main engines.
Ice, or even slush, could seriously damage the heat shielding tiles of the Shuttle if impact occurred during lift off when the shuttle achieves speeds of Mach 3 (~2100 mph). Tests of potential impact damage were performed in NASA’s wind tunnel, where it was discovered that (counterintuitively) slush was just as damaging to the ceramic tiles as solid ice.
The fully-assembled Shuttle stack, orbiter, ET and twin Solid Rocket Boosters, will be mounted on the Mobile Launcher Platform and delivered to the pad via a Crawler Transporter. The four-mile journey from the Vehicle Assembly Building to the pad takes about six hours.
Launch of Discovery on its Return to Flight mission (STS-114) is targeted for July 13 with a launch window that extends to July 31. During the 12-day mission, Discovery’s seven-person crew will test new hardware and techniques to improve Shuttle safety and deliver supplies to the International Space Station.
(Where we say “Juju Speed John Glenn”.)