Space shuttle Discovery is on its way to the International Space Station (ISS), blasting off at 6:21 a.m. local time Monday from NASA's Kennedy Space Center without any of the weather– or equipment–related delays that have plagued the past several launches.

The shuttle is ferrying a seven-member crew to the ISS to perform a complex and expensive construction project and to deliver additional sleeping quarters, exercise equipment and racks for science experiments. The 13-day mission is expected to include three space walks, each of which will last about six and a half hours.

The first space walk is to replace an ammonia tank assembly. Ammonia is used to move excess heat from inside the station to the radiators located outside. During the second space walk, astronauts will retrieve a Japanese experiment from the station's exterior. The final walk is being done to replace a failed gyroscope that is part of the station's navigation system.

STS-131 (pdf), the mission's official name, is the 33rd shuttle mission to the station and Discovery's 38th flight overall. This is the second of five shuttle missions planned for 2010, after which NASA expects to shut down the space shuttle program.

Discovery's crew for STS-131 comprises commander Alan Poindexter, pilot Jim Dutton, and mission specialists Rick Mastracchio, Dottie Metcalf-Lindenburger, Stephanie Wilson, Naoko Yamazaki and Clay Anderson. Yamazaki is a member of the Japan Aerospace Exploration Agency astronaut corps; the other six are NASA astronauts.

Time elapsed image of Discovery's Monday launch courtesy of NASA/Ben Cooper