Smaller image credit: NASA; smaller image source; larger image credit: STS-41B, NASA; larger image source
In 1984, astronaut Bruce McCandless made this untethered spacewalk--the first ever, and one of only a few. He maneuvered with a "jet pack" strapped to his body as he orbited Earth at about 18,000 miles an hour. Click on the image to see McCandless at his maximum distance from the shuttle.
Whenever the jet pack's engines were off, McCandless was in free fall--the only force on him was Earth's gravity (neglecting air resistance and the gravitational attraction of the shuttle). To learn more, visit Footloose and this APOD page.