The countdown for the launch of the Discovery mission is on, and astronauts in charge of landing the spacecraft are continuously practicing landing maneuvers.   The spacecraft will launch from Launch Pad 39A on Wednesday night, at 9:20 p.m. EDT.

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.

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.

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 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.