This is must be the most known picture in the Internet and in the whole world. But it so great that it will never get old hence my choice to post it.
Some history just in case. The pictures depict American astronaut Bruce McCandless II who became the first to make an untethered spacewalk thanks to nitrogen jet propelled backpack called the Manned Maneuvering Unit (MMU) in 1984.
At about 100 meters from the cargo bay of the space shuttle Challenger, Bruce McCandless II was further out than anyone had ever been before "free-flying" to a distance of 320 feet away from the Orbiter.
MMUs are no longer used due to security problems, but astronauts now wear a similar backpack device in case of emergency.