OTD…Sept. 19 and Endeavour retirement

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

#OTD in 1984…Challenger launched the Earth Radiation Budget Satellite

#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