Spaceflight

Space Shuttle Discovery’s crew of seven have boarded the Orbiter as the countdown continues smoothly towards the 1948GMT launch of International Space Station logistics mission STS-121.
Launching from pad 39B at Kennedy Space Center (KSC) STS-121 is the eighteenth US mission to the ISS and the 32nd flight for Discovery.
The mission commander is Steven Lindsey and his crew of five NASA astronauts comprises, pilot Mark Kelly, mission specialists Michael Fossum, Lisa Nowak, Stephanie Wilson and British born Piers Sellers; and European Space Agency astronaut Thomas Reiter joins them to be transported to the space station to become the third member of the current ISS Expedition 13.

This second return to flight mission will see supplies delivered, replacement of a pump and a communication umbilical reel assembly for the ISS’s mobile transporter and Shuttle thermal protection system tile repair techniques tested.
Discovery's crew members had a wake-up call at 0900 and ate their traditional launch-day breakfast at the Operations and Checkout Building.
Lindsey and two crew members attended a flight controllers briefing about the weather conditions at KSC and alternate landing site availability.
The presence of storm clouds close to KSC could still delay the launch and NASA’s engineers are continuing to study a failed thruster heater in the Orbiter's left orbital maneuvering system pod.
At around 1400 the crew went to the suiting room to put on the orange flight suits that contain an oxygen supply, communications equipment and a temperature control system. After suiting up, the astronauts went to the vehicle waiting to take them to pad 39B.

By Rob Coppinger in Orlando