Teacher-astronaut Barbara Morgan

This shuttle mission is also a mission carrying key elements needed for the continued construction of the international space station.

At Cape Canaveral, on television, and in classrooms hundreds of young and old spectators waited anxiously for Endeavour's liftoff Wednesday.

"zero', and liftoff of space shuttle Endeavour, expanding the international space station while creating an international classroom in space."

Teacher-astronaut Barbara Morgan and her six crewmates soared smoothly into the evening sky over Cape Canaveral. Eight and half minutes later, and reaching speeds of more than 18,000 kilometers per hour these words from mission control.

Space Shuttle Endeavour is launched

"External tank separation confirmed. Endeavour now in its preliminary orbit for Barbara Morgan and her crewmates, class is in session."

Morgan is finally fulfilling the space program's quest to send a teacher into space. It was 21 years ago that teacher Christa McAuliffe and the Challenger crew was lost 73 seconds after take off. Morgan was McAuliffe's backup that day.

On Thursday, cameras attached to Endeavour's robotic arm looked for damage to the shuttle's protective foam tiles.

Four or five small pieces of debris came off during launch. Not a concern, according to NASA officials on the ground who are further studying inspection data.

On this mission, NASA astronauts are installing a massive starboard truss to the station. It is a two-ton spacer going between two solar arrays  the second to be installed in 2008.

Placement of the truss continues Saturday with the first of three, possibly four spacewalks. This is a Endeavour's 20th mission and its first in five years.