Skylab 3 (also SL-3 and SLM-2) was the second manned mission to the first American space station, Skylab. The mission began July 28, 1973, with the launch of three astronauts on the Saturn IB rocket, and lasted 59 days, 11 hours and 9 minutes. Read more
Continued maintenance of the space station and extensive scientific and medical experiments. Completed 858 Earth orbits and 1,081 hours of solar and Earth experiments; three EVAs totalled 13 hours, 43 minutes. Source