Space launches rarely go according to plan, so NASA’s decision to postpone the launch of Discovery for no earlier than February 19 should come as no surprise. The space agency revealed that they needed more time to assess an issue associated with a flow control valve in the shuttle’s main engines.
The shuttle Discovery is preparing for a 14-day mission, during which it will deliver the final set of solar array wings for the International Space Station to complete the station’s truss.
The STS-119 mission will include seven astronauts: pilot Tony Antonelli, Mission Specialists Joseph Acaba, John Phillips, Steve Swanson, Richard Arnold, Japan Aerospace Exploration Agency astronaut Koichi Wakata, and Commander Lee Archambault, in charge of the crew.
The mission was initially scheduled to launch on February 12, however NASA decided to take more time to inspect the valves and assess what would happen if the November situation would repeat itself. Back then, one of the valves in shuttle Endeavour was found to have suffered damage after the mission was over, which prompted NASA specialists to take precautionary measures this time.
All three valves that channel gaseous hydrogen from the engines to the external fuel tank have been removed, inspected and reinstalled back. NASA announced that on February 10, a meeting to assess the analysis will take place. In addition to that, two days later, the flight readiness review team will establish the exact date for the launch.
The Discovery flight was intended to provide the necessary support for the station’s crew of six, as well as deliver the needed arrays that will provide electricity for the scientific experiments to be carried on the station.
According to NASA, the mission will include four spacewalks, during which the crew will install the final set of solar arrays, in addition to replacing a failed unit for the system that converts urine into potable water. Each of the four spacewalks is scheduled to last approximately 6.5 hours.
The first one is scheduled for flight day 5 of the mission, when Mission Specialist John Phillips and astronaut Koichi Wakata will use the station’s robotic arm to put the S6 truss into position, while Mission Specialists Steve Swanson and Richard Arnold will assist them from the outside with the installation, in addition to unstowing the solar array blanket boxes on the array structure.
On day 7, Mission Specialists Steve Swanson and Joseph Acaba will prepare a set of batteries for removal on the P6 truss, in addition to deploying attachment fixtures on the P3 and S3 trusses and hook up new fluid connections between the P1 and P3 truss segments.
The third spacewalk will take place on day 9, when Mission Specialists Richard Arnold and Joseph Acaba will relocate equipment carts, remove and repair circuit breakers, lubricate the robotic arm, and install thermal blankets on the Dextre robot.
The last spacewalk is scheduled for day 11, when Mission Specialists Steve Swanson and Richard Arnold will install a GPS antenna on the exterior of the Japanese logistics module, as well as take pictures of the radiators on the truss.
