OTD…Oct. 7 and STS-112

#OTD in 1995, Endeavour launched on the ASTRO-2 astronomy mission:

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 Discovery in 1991 on a Defense Department research flight