OTD…July 15 and STS-127

#OTD in 2012…Crowds cheer as Endeavour traverses though Los Angeles

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 1997…Atlantis launched on the seventh joint docking mission with Russia’s space station Mir