Table of Contents

Astronauts

Space Shuttle Crew

The crew of mission STS-52 break from their busy mission aboard Space Shuttle Columbia to pose for the traditional in-flight crew portrait. CSA Astronaut Steve MacLean, payload specialist, is in the centre. (Photo: NASA)

Space operations astronauts can be assigned to the Space Shuttle program or the International Space Station (ISS) program, whereas invited astronauts can only participate in the ISS program.

While Space Shuttle crew members need to be highly skilled in every Shuttle system for operations to run smoothly and safely, astronauts are still assigned to specialized duties onboard the Shuttle in one of the following positions:

• Pilot astronauts, like pilots and co-pilots on airplanes, are responsible for the actual flight, navigation, and landing of the Space Shuttle. A pilot astronaut can fill either of two positions on a Shuttle flight:
  
  
  • Commander: During a Shuttle flight, the commander has responsibility for the vehicle, the crew, and the safety of the flight. The commander, in essence, directs the Shuttle mission and is ultimately responsible for its success.
  • Pilot: Like an airplane co-pilot, a Shuttle pilot helps the commander operate and control the Shuttle. Under rare circumstances of limited crew size, pilots may also be called upon to perform some mission specialist tasks such as retrieving and/or deploying satellites using the Shuttle's Canadarm. Pilots can only do this if they have undergone mission specialist training.
     
• Mission specialists are responsible for coordinating Shuttle operations, planning crew activity, and managing the use of consumables such as food, fuel, and oxygen. Mission specialists are also responsible for all experiments (payload operations), and for performing spacewalks, if required. All CSA astronauts currently on active flight status are mission specialists.

• Payload specialists are non-NASA astronauts who are occasionally sponsored to travel on the Shuttle to fulfill specialized duties. Although mission specialists are considered first for selection on flights where additional crewmembers are needed, payload specialists are sometimes recruited for their expertise, which may relate to the payload experiments conducted on the mission, or to fulfill other unique crew requirements.
  
  

STS-85 Mission Specialist Stephen Robinson (left) and Payload Specialist Bjarni Tryggvason check out an emergency egress slidewire basket at the 195-foot level of Launch Pad 39A during Terminal Countdown Demonstration Test (TCDT) activities for that mission. (Photo: NASA)

Each Shuttle flight requires a minimum of four crewmembers to operate safely, of which there must be at least one commander, one pilot, and two mission specialists. Until 1995, Canadian astronauts were only authorized to fly on the Shuttle as payload specialists. Today, however, all Canadian astronauts are trained as mission specialists.