(December 2001)--- These seven astronauts are in training for the STS-110 mission, scheduled to visit the International Space Station early next year. In front, from the left, are astronauts Stephen N. Frick, pilot; Ellen Ochoa, flight engineer; and Michael J. Bloomfield, mission commander; In the back, from left, are astronauts Steven L. Smith, Rex J. Walheim, Jerry L. Ross and Lee M.E. Morin, all mission specialists.  

STS-110 was a Space Shuttle mission to the International Space Station (ISS) flown by Space Shuttle Atlantis. The main purpose was to install the S0 Truss segment, which forms the backbone of the truss structure on the station.

The main purpose of STS-110 was to attach the S0 Truss segment to the International Space Station (ISS) to the Destiny Laboratory Module. It forms the backbone of the station to which the S1 and P1 truss segments were attached (on the following missions STS-112 and STS-113, respectively).

STS-110 also delivered the Mobile Transporter (MT), which is an 885 kg (1,950 lb) assembly that glides down rails on the station integrated trusses. During the next shuttle mission, STS-111, the Mobile Base System (MBS) was mounted to the MT. This Mobile Servicing System (MSS) allows the Canadarm2 to travel down the length of the installed truss structure.