Manned maneuvring unit space walk, 1984. Astronaut Bruce McCandless floats free above the Earth in his manned manoeuvring unit (MMU) on 7th February 1984, during the 10th space shuttle flight (mission 41B). McCandless, who helped design the MMU, was the first person to fly it, thus becoming the first 'human satellite' in orbit around the Earth. The MMU is propelled by small nitrogen thrusters which are controlled by the astronaut's hands. Because no tether attaches the astronaut to the spacecraft, it gives much greater mobility than was available to earlier spacewalkers. Mission 41B was launched from the Kennedy Space Center (KSC) on 3rd February 1984, and landed back at KSC on 12th February.