During the Discovery's mission, two pairs of astronauts are to make four spacewalks to connect components of the truss and the new docking port to the station.
The plan calls for Michael L. Gernhardt, a veteran of three earlier spaceflights, and James F. Reilly, who flew on one previous shuttle mission, to make three spacewalks to secure the air lock to the starboard side of the Unity connecting node and attach the gas canisters.
During his stay aboard Mir, he made two spacewalks.
The men made two spacewalks during the mission, the second occurring on Feb. 9.
The astronauts delivered a $390 million girder to the space station and made three spacewalks to install it.
During their week at the space station, astronauts made three spacewalks to attach the $600 million solar wings, hook up the cables and then tighten the right wing, which was too slack.
John Grunsfeld, who made three spacewalks during the mission, told Senator Mikulski and her colleagues that there was hardly a classroom in America that did not have a poster with some Hubble picture in it.
Having made three spacewalks totaling nearly 21 hours during the mission, he said he was awestruck by the enormousness of the space station ("bigger than a football field") and the human and political achievement it represented.
During that time she made three spacewalks to remove and replace a failed pump module.
The four, Leroy Chiao, William S. McArthur, Peter J. K. Wisoff and Michael E. Lopez-Alegria, are each to make two six-and-a-half hour spacewalks in four days, doubling the time crews have spent working outside the station on four earlier flights to the complex.
