#NASA astronauts Chris Cassidy and Bob Behnken start their second spacewalk together on July 1 to continue upgrading power systems on the International Space Station.
In This Story: NASA
The National Aeronautics and Space Administration is an independent agency of the U.S. Federal Government responsible for the civilian space program, as well as aeronautics and space research. NASA was established in 1958, succeeding the National Advisory Committee for Aeronautics.