OTD…July 31 and STS-46

Neil Armstrong, Buzz Aldrin and Michael Collins launched today in 1969 aboard Apollo 11 for one of the defining moments of the 20th century — man’s first landing on the moon.

Today in 1996…The launch of Columbia and the ill-fated Tethered Satellite System. Watch the liftoff:

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.