OTD…April 6 and STS-41C

#OTD in 1997…Columbia launched on the reflight of her shortened Microgravity Science Laboratory mission

Studying the atmosphere as part of NASA’s Mission to Planet Earth was the objective of shuttle Atlantis’ STS-45 mission in March 1992.

#OTD in 2007…NASA’s Dawn probe launched to explore the uncharted worlds of Vesta and Ceres in the heart of the asteroid belt.