OTD…Aug. 10 and STS-105

#OTD in 1988…Discovery returned Americans to space after the Challenger accident

Today marks the 40th anniversary — July 20, 1976 — of the first U.S. robotic landing on another planet by the Viking 1 spacecraft on Mars.

#OTD in 1982 the 3rd launch of the space shuttle and in 1996 the 3rd Mir docking missioN