WASHINGTON, June 16 (Xinhua) -- Early Saturday morning, U.S. astronaut Sunita Williams set the new record of the longest-duration single space flight by a woman, NASA announced on its official website.

Williams passed the previous record of 188 days, 4 hours at 1:47 a.m. EDT (0547 GMT) on Saturday as the Atlantis crew and Expedition 15 crew members slept aboard the shuttle and the International Space Station.

Williams began her space flight in December 2006, when she traveled to the station with shuttle Discovery. She served six months as a space station crew member. The previous record set by Shannon Lucid on a mission to the Russian Mir space station had stood since 1996.

The workday schedule for Williams and her crewmates is filled with cargo transfers, spacewalk preparations and a Joint Crew News Conference.

The crews will get ready for the fourth spacewalk of Atlantis mission by preparing tools and spacesuits that will be used by Mission Specialists Patrick Forrester and Steven Swanson. The excursion is set to begin at 12:53 p.m. (1653 GMT) on Sunday.

Efforts to bring the Russian navigation computers back to full operation continue on Saturday. On Friday, Russian flight controllers and the station crew were able to power-up two lanes of the Russian Central Computer and two lanes of the Terminal Computer by using a jumper cable to bypass a faulty secondary power switch.

Flight controllers began sending commands overnight to restart some systems. The Central Computer is now communicating with the U.S. command and control computer, and the Terminal Computer is communicating with U.S. navigation computers. The plan calls for more system restarts on Saturday.

The failed Russian navigation computers provide backup attitude control and orbital altitude adjustments. For now, the station's control moment gyroscopes are handling attitude control, with the shuttle's propulsion system providing backup.