Kevin R. Kregel, Mission Commander (back, second from left): Making his fourth flight into space, Kregel has overall responsibility for the success and safe conduct of the STS 99 mission. His crewmates will be divided into two three-person teams working 12-hour shifts to conduct round-the-clock science activities. Kregel will lead the Red team shift. He also is in charge of the operation of an HDTV camera during the flight, as well as the EarthKam payload.

Dominic L. Pudwill Gorie, Pilot (back, second from right): Gorie (Commander, USN) will lead the STS 99 Blue team shift on this, his second flight into space. A veteran of the STS 91 mission, Gorie will operate an HDTV camera and the EarthKam payload during the flight and will oversee orbiter operations during his 12-hour shift on the flight deck. Gorie would also serve as an intravehicular crew member, or choreographer, in the event a contingency spacewalk (EVA) is required.

Janet L. Kavandi, Mission Specialist (back, right): In her second flight into space, Kavandi will be the flight engineer during Endeavour's launch and landing phases, sitting behind Kregel and Gorie on the flight deck. She will work on the Red team shift, responsible for SRTM operations along with Thiele. Kavandi would perform a spacewalk along with Thiele if a contingency arose during the mission.

Janice E. Voss, Mission Specialist (back, left): Voss will work on the Blue team shift during STS 99 and, as Payload Commander, has the overall responsibility for the operation of the SRTM systems during the flight.

Mamoru Mohri, Mission Specialist (front, left): NASDA astronaut Mohri is making his second flight into space, having first flown as a Payload Specialist on STS 47. Mohri will join Voss for responsibility of the SRTM payload during the Blue team shift and would serve as an intravehicular crew member, or spacewalk choreographer, in the event a contingency spacewalk was required. Mohri will also operate an HDTV camera during the flight and conduct a number of secondary experiments.

Gerhard P.J. Thiele, Mission Specialist (front, right): In his first flight into space, European Space Agency astronaut Gerhard Thiele will work on the Red team shift, responsible for SRTM operations, including the deployment and retraction of the 200-foot (60-meter) long boom from Endeavour's cargo bay upon which one of the flight's radar systems is mounted. Thiele would also be one of two spacewalking crew members along with Janet Kavandi, in the event a contingency EVA is required during the flight.