UPDATE: Launch delayed. Stay up to date at Spaceflight Now's Mission Status Center
"The STS-119 mission will deliver to the station the final set of solar arrays needed to complete the station's complement of electricity-generating solar panels, and through them support the station's expanded crew of six in 2009."
"Over the past year, one new connecting node – Harmony – and two new international partner laboratories – the European Columbus and the Japanese Kibo – have been added to the space station, expanding its capacity for science experiments. And one of the reasons the crew is being expanded is to have more hands aboard performing those experiments. The additional electricity provided by the new solar arrays will help power those experiments."
STS-119 crew member Koichi Wakata of the Japan Aerospace Exploration Agency (JAXA) will stay aboard the station after the shuttle Discovery leaves replacing Sandy Magnus who arrived on the station in November. Wakata will be the first JAXA station crew member.
STS-119 crew member Joe Acaba is a part of the NASA educator in space program. He spent two years in the U.S. Peace Corp, one year teaching at Melbourne High School, and four years teaching at Dunnellon Middle School (both in Florida). Although he was born in California, both his parents are from Puerto Rico and so he is the first person of Puerto Rican heritage to go into space.
Richard Arnold, another member of the STS-119 crew is also a teacher and a member of the Astronaut educator program. Since 1987 he has taught at middle and college preparatory schools in Maryland, Morocco, Saudi Arabia, Indonesia, and Romania.