OTD…June 20 and STS-78 and NROL-38

#OTD…The first launch of Challenger in 1983 and Columbia’s shortened Spacelab mission in 1997

#OTD in 1994…Discovery launched to develop new techniques for monitoring Earth’s environment from space…and in 2006…Construction of the space station resumed as Atlantis delivered a power-generating truss

#OTD in 2001…Discovery launched on an International Space Station crew exchange mission