The term "astronaut" derives from the Greek words meaning "space
sailor," and refers to all who have been launched as crew
members aboard NASA spacecraft bound for orbit and beyond.
Since the inception of NASA's human space flight program,
we have also maintained the term "astronaut" as the title
for those selected to join the NASA corps of astronauts
who make "space sailing" their career profession. The
term "cosmonaut" refers to those space sailors who are
members of the Russian space program.
The crew of each launched spacecraft is made up of astronauts
or cosmonauts drawn from the various categories described
in these pages. The crew assignments and duties of commander,
pilot, space shuttle mission specialist, or International
Space Station flight engineer are drawn from the NASA professional
career astronauts. A special category of astronauts typically
titled "payload specialist" refers to individuals selected
and trained by commercial or research organizations for
flights of a specific payload on a space flight mission.
At the present time, these payload specialists may be cosmonauts
or astronauts designated by the international partners,
individuals selected by the research community, or a company
or consortia flying a commercial payload aboard the spacecraft.
The links to the left will direct you to biographical
information on the astronauts. These biographies are prepared
by the Astronaut Office of the Johnson Space Center and are provided through
the Internet as a public service to the World Wide Web