Feb. 7, 1984: STS-41-B was the tenth NASA Space Shuttle mission and the fourth flight of the Space Shuttle Challenger. It launched on February 3, 1984, and landed on February 11 after deploying two communications satellites. It was also notable for including the first untethered spacewalk. Astronaut Bruce McCandless II, mission specialist, participates in a extra-vehicular activity (EVA), a few meters away from the cabin of Space Shuttle Challenger. He is using a nitrogen-propelled hand-controll