Discovery will lift off no earlier than May 30 , NASA says . Space is concerned about a valve in the main engine . A decision on the launch date will be made February 12 , after more analysis and testing of the part . This will be the shuttle 's 28th mission to the international space station . The shuttle will deliver the final shipment of solar panels for the station .
Discovery will lift off no earlier than May 30 , NASA says . Space is concerned about a valve in the main engine . This will be the shuttle 's 28th mission to the international space station . The shuttle will deliver the final shipment of solar panels for the station .