crewed spaceflight 123rd Space Shuttle flight since STS-1 98th post-Challenger mission 10th post-Columbia mission 11th flight remaining in the shuttle program 26th flight to the ISS 35th flight for shuttle Discovery 3rd shuttle mission in 2008 Shuttle Processing On April 26, 2008 Discovery was rolled over to the Vehicle Assembly Building (VAB) from its processing bay in the Orbiter Processing Facility. Once in the VAB it was lifted vertically and mated with its external tank and solid rocket boosters on April 28, 2008. At the end of a week-long prep schedule on May 2, 2008, at 23:47 EDT the stack was rolled out to launch pad 39A on top the Mobile Launch Platform. Carried by the Crawler Transporter, Discovery arrived and was secured at LC-39A on May 3, 2008, at 06:06 EDT. The payload canister containing the JEM was rolled out to the Payload Changeout Room at the pad on April 29, 2008, and was later installed into Discovery's payload bay on May 5, 2008. The STS-124 crew arrived at Kennedy Space Center on May 6, 2008, for the 3-day Terminal Countdown Demonstration Test and returned to Johnson Space Center on May 9, 2008, after completion of the launch dress rehearsal. After many flight readiness review tests, Discovery was given a go for a May 31, 2008, launch. Discovery launched on May 31, 2008, at 21:02 UTC. Mission timeline May 31 (Flight day 1, Launch) The Space Shuttle Discovery launched from the Kennedy Space Center at 17:02 EDT local time. Debris from the fuel tank was minimal. "While we've all prepared for this event today, the discoveries from Kibo will definitely offer hope for tomorrow," said Discoverys commander Mark Kelly just before launch. "Now stand by for the greatest show on Earth." Launch pad damage One of the trenches at launch pad 39A that channels flames away from the shuttle during lift-off was significantly damaged. The subsequent mishap investigation found that the damage was the result of carbonation of epoxy and corrosion of steel anchors which held the refractory bricks in place. These had been exacerbated by the fact that hydrochloric acid is an exhaust by-product of the solid rocket boosters. Repairs to the trench were completed before the STS-125 mission's then scheduled launch attempt on October 8, 2008. In fact STS-125 finally launched in May 2009, and in the meantime STS-126 (November 2008) and STS-119 (March 2009) had both