OTD…April 4 launches of STS-6 and 83

#OTD in 1996…Columbia launched on a life sciences and microgravity flight.

#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…Launch of a 1994 Space Radar Lab mission on Endeavour