The space shuttle Endeavour is on its way to begin the longest space station mission ever.

Endeavour and its seven-member crew took off from the Kennedy Space Center Tuesday morning in a rare after-dark launch.

The blastoff lit up the sky for miles around just before the space vehicle disappeared into the darkness.

The crew is on a 16-day mission to build a Canadian robot and add the first part of a massive Japanese lab at the station.

The astronauts will perform five spacewalks during the mission -- the most ever planned during a shuttle visit.

They'll also use the mission to try out a caulking gun and a high-tech goo on thermal tile samples, a test that's part of NASA's ongoing safety efforts following the Columbia disaster.

The mission is the second of six planned shuttle missions this year.

One of the highlights of the mission will be the deployment of a 12-foot, two-armed robot that will help with space station construction and maintenance.

The robot, called Dextre, was built by the Canadian Space Agency. It is nearly 8 feet wide, and each arm extends 11 feet.

The crew will also deliver the first part of a Japan's Kibo lab and storage facility.

It's only the second scheduled nighttime launch since the 2003 Columbia disaster.

When flights resumed, NASA allowed only daytime launches in order to track potential damage. Debris from the external fuel tank punched a hole in Columbia's wing, leading to its destruction when it tried to re-enter the atmosphere.

NASA no longer requires daylight launches because of better insulation and radar tracking.

The flight is commanded by Dominic Gorie with Gregory H. Johnson serving as pilot. The crew also includes Mission Specialists Rick Linnehan, Robert L. Behnken, Mike Foreman, Garrett Reisman and Japanese astronaut Takao Doi.

The mission is designated STS-123.