Stats: Delta 4 history and manifest

Watch NASA’s news conference to preview three spacewalks outside the International Space Station planned for late March and early April to prepare for the future arrival of U.S. commercial crew spacecraft and upgrade station hardware.

The United Launch Alliance Delta 2 rocket lifts off with NASA’s SMAP observatory at 6:22 a.m. local time on Saturday, Jan. 31 from Vandenberg Air Force Base in California.

The spacecraft will journey back to Earth without the two astronauts it launched with back on June 5. Undocking is set for 6:04 p.m. EDT (2204 UTC) with landing just after midnight on Saturday.