OTD…Jan. 13 and STS-54

#OTD in 1993…Endeavour launched with the first Spacehab module and retrieval of the European EURECA satellite

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 2006…A star-spangled start to Discovery’s STS-121 mission