The Soviets beat Americans to spacewalking. On March 18, 1965, Aleksey Leonov became the first human to walk in space. The image is a still from the external movie camera attached to his vessel, the Soviet Voskhod 2.
Mission STS-41b marked the first checkout of the Manned Maneuvering Unit (MMU) and Manipulator Foot Restraint (MFR). McCandless made the first untethered free flight on each of the two MMUs carried on board, thereby becoming the first person ever to make an untethered spacewalk.
Astronaut Robert L. Stewart becomes the second man to participate in an untethered EVA using the MMU. He was also the first member of the U.S. Army to go into space.
Astronaut Mark Lee testing the Simplified Aid for EVA Rescue (SAFER) system for NASA in 1994. SAFER is a backpack propulsion unit that incorporates small nitrogen thrusters controlled by hand and moderated by computer. Pictured, Lee jets about the bay of Space Shuttle Discovery, over 200 kilometers above Earth in the first untethered space walk in ten years. Lee was not in danger -- the shuttle could have been used to retrieve him. SAFER, smaller than the Manned Maneuvering Unit, is designed as a backup system to help astronauts in the unlikely event that they become too separated from their work outside the International Space Station.
Astronaut Chris A. Hadfield, mission specialist representing the Canadian Space Agency (CSA), is seen near the Canadarm2 as the new robotics tool for the International Space Station (ISS) grasps the Spacelab pallet. Hadfield participated in two days of extravehicular activity (EVA) on the STS-100 mission.