OTD…Jan. 28 and STS-51L

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.

Veteran CBS News correspondent Bruce Hall was not on the air when the shuttle Challenger blasted off 30 years ago Thursday. It was, after all, the 25th shuttle flight, the first of 16 planned for 1986, and news agencies were backing off expensive, remote coverage of what increasingly appeared to be a routine event.

#OTD in 1998…The launch of Discovery on final shuttle-Mir docking mission