Becoming an Astronaut (pg. 2)
Astronauts - The Payload Commander
A Payload Commander is responsible for the coordination of any experiments that are carried out during a space mission. For example, over 80 experiments were performed during the 16-day, STS-107 Columbia mission. One study involved the growth of prostate cancer tissue, while another showed that carpenter ants don't seem to notice weightlessness. A Payload Commander is always a NASA astronaut.
Astronauts - The Payload Specialist
A Payload Specialist is someone other than a NASA astronaut, who is assigned to a space mission by either a corporation or another country to oversee and help with a certain mission experiment. Payload Specialists can come from universities, research centers, government agencies, businesses or other nations that use the space shuttle. Usually a Payload Specialist will work on one specific experiment, but if it looks like a crew has too much work to handle on their own, the Payload Specialist will often lend a hand.
Astronauts - The Mission Specialist
There are usually three Mission Specialists aboard a space shuttle. They must have knowledge of all the experiments taking place on board, unless a Payload Specialist is in charge of the experiment and will not require help with it. A Mission Specialist also must know about safety procedures, shuttle operations, crew activity planning and the usage of consumables (food) on board the shuttle. In order to become a Mission Specialist astronaut, you have to pass a NASA Class II space physical to make sure you are in top physical condition.
- Click here to read more about the types of astronauts that NASA sends into space.