NASA booth at the USA Science and Engineering Festival
GRAPHIC : NASA offers food and protective heat tiles to schools to help students learn about the space program.
STS-123 mission specialist Richard Linnehan participates in a spacewalk outside the International Space Station. Photo: NASA
A study determines more astronauts are needed.
The Challenger Flight Crew who died Jan. 28, 1986
January 28 marks the 25th anniversary of the Challenger disaster.