July 20, 1969: Lunar landing of Apollo 11

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.

Dave Scott, Jim Irwin and Al Worden left for the Moon today in 1971 aboard Apollo 15 bound for Hadley rille with the first Lunar Roving Vehicle.

#OTD in 1983…Challenger lifts off on the first nighttime shuttle launch…and Discovery launches on her inaugural Spaceflight