Technicians are removing Discovery’s three gaseous hydrogen flow control valves. Part of the main propulsion system, the valves channel gaseous hydrogen from the main engines to the external tank. Photo credit: NASA/Dimitri Gerondidakis

Space shuttle Discovery will deliver the International Space Station’s fourth and final set of solar arrays, completing the station’s backbone, or truss structure. (see below launch date and timeline)

The arrays will provide enough electricity to power science experiments and support the station’s expanded crew of six. Altogether, the station’s arrays can generate about 120 kilowatts of usable electricity — enough to provide about 42 2,800-square-foot homes with power. 

The 14-day flight will include four spacewalks, lasting about 6.5 hours each, to help install the S6 truss segment to the right side of the station. 

STS-119 is the 125th space shuttle flight, the 28th flight to the station, the 36th flight of Discovery, and the first flight in 2009.

Mission: STS-119 

Orbiter: Discovery 

Primary Payload: S6 Truss Segment and U.S. Solar Arrays

Target Launch Date: March 11

Launch Time: 9:20 p.m. EDT

Launch Pad: 39A 

Mission Duration: 14 days

Check out the coolest flash of the filght’s timeline

Landing Site: Kennedy Space Center, Florida