OTD…April 9 and STS-59

#OTD in 2007…Discovery launched Harmony as the gateway to future international science laboratories

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…Launch of Columbia in 1998 on the Neurolab Spacelab mission