Williams, whose Twitter username is Astro_Jeff, is also making use of a blog and short video clips to provide a behind-the-scenes insight into his experiences at the Gagarin Cosmonaut Training Center in Star City, Russia. Once in orbit, Williams will become the first space station commander to share his experiences using Twitter, NASA said.
Williams will launch to the space station aboard a Soyuz spacecraft with Max Suraev, the commander, and spaceflight participant Guy Laliberte from the Baikonur Cosmodrome in Kazakhstan Sept. 30.
Williams will become a flight engineer for the Expedition 21 crew when he arrives at the space complex and later will command Expedition 22. He will spend six months in space.
Williams will be making his third trip to space. NASA said he's has logged more than 193 days in space, including more than 19 hours during three spacewalks.
Williams' blog is available at http://blogs.nasa.gov/cm/blog/2089.