Launch from Cape Canaveral (KSC); landing on Edwards AFB. Mission ISS-08-6A MPLM Raffaello.

The highest priority objectives of the flight were the installation, activation and checkout of the Canadarm2 robotic arm on the station. The operation of the arm is critical to the capability to continue assembly of the International Space Station, and was also necessary to attach a new airlock to the station on the subsequent shuttle flight.

Other major objectives for Endeavour’s mission were to berth the Raffaello logistics module to the station, activate it, transfer cargo between Raffaello and the station, and reberth Raffaello in the shuttle's payload bay. Raffaello is the second of three Italian Space Agency-developed Multi-Purpose Logistics Module that were launched to the station. The Leonardo module was launched and returned on the previous shuttle flight, STS-102, in March 2001.

Following a two day solo flight the Endeavour docked with the ISS on April 21, 2001 and common work with the ISS expedition two followed.

The first EVA was performed by Chris Hadfield and Scott Parazynski on April 22, 2001 (7h 10m) to install the Canadian built robotic arm (57.7 foot long) called: Canadarm2. Chris Hadfield was the first Canadian in free space.

The second and final EVA by Chris Hadfield and Scott Parazynski occured on April 24, 2001 (7h 40m) to connect the Power and Data Grapple Fixture circuits for the robotic arm.

Remaining objectives included the transfer of other equipment to the station such as an Ultra-High Frequency communications antenna and a spare electronics component to be attached to the exterior during space walks. Finally, the transfer of supplies and water for use aboard the station, the transfer of experiments and experiment racks to the complex, and the transfer of items for return to Earth from the station to the shuttle were among the objectives.

The temporary loss of Command and Control Computer number one (C&C1) forced one day bonus docking time.