On this day in 1984…… U.S. Astronaut Bruce McCandless became the first human to fly in space untethered.. He unhooked a lifeline and used a gas-powered jet-pack called the Manned Maneuvering Unit to fly almost 300 feet away from the U.S. space shuttle Challenger, which was orbiting the Earth, and back again; it was the first of two space shuttle missions Astronaut McCandless made. Captain Bruce McCandless II was born in Boston, Massachusetts...