This will be Rick's third spaceflight, having served as a pilot for the STS-58 and STS-76 missions. A Lieutenant Colonel in the US Air Force, Rick became an astronaut in 1991.

Scott (Scooter) will make his first spaceflight on STS-90. He is a Commander in the US Navy, and became an astronaut in 1995. 

Rick flew in space as part of the STS-78 payload crew. Before his selection as an astronaut in 1992, he was the chief clinical veternarian for the Navy Marine Mammal Project.

Kay is a member of the 1995 astronaut class, and holds the rank of Commander in the US Naval Reserve.  Prior to her selection she worked as an engineer and supervisor at the Kennedy Space Center.

In 1992 Dave was selected as an astronaut by the Canadian Space Agency.  Subsequently he joined the 1995 NASA astronaut class. An experienced neuroscientist and physician, he will be making his first flight.

Jay has been involved in spaceflight and clinical research for more than 10 years, and served as an alternate payload specialist for STS-58.  He is sponsored by Dartmouth Medical School for his first flight.

Jim has been conducting spaceflight research for more than 5 years, and will be making his first spaceflight.  He is sponsored by Penn State University and is a co-investigator for one of the Neurolab experiments. Penn State has its own Jim Pawelczyk/Neurolab site.

Alex has supported five previous shuttle missions as a project veterinarian.  He is sponsored by the University of Tennessee at Memphis.

Chiaki is a Japanese astronaut sponsored by NASDA, and has served as an alternate payload specialist for STS-47. She flew in space as a payload specialist aboard STS-65 in 1994. Her clinical specialty is surgery and she is an accomplished research scientist.