NASA astronaut Suni Williams is an official participant in the Boston Marathon.  She will run the distance of the marathon on the exercise treadmill located on the International Space Station (ISS).  This will mark the first time an astronaut on-orbit has participated in a marathon event.

Williams is a veteran marathoner and has been onboard the station since December 2006 as a member of the Expedition 14 ISS crew. Her sister, Dina Pandya and a fellow NASA astronaut, Karen Nyberg, will also run the race in Boston. As Williams runs the race on the station treadmill, she will orbit the Earth at least twice in the process, running as fast as eight miles per hour but flying more than five miles each second.

Williams has been training on the ISS treadmill for months.  She runs four times a week; doing two long runs and two short runs.  Crews on the ISS are required to exercise on the treadmill, a stationary bike and a resistive exercise machine to counter loss of bone density and muscle mass during their long stay in weightless space.

"In microgravity, both of these things start to go away because we
don't use our legs to walk around and don't need the bones and muscles to hold us up under the force of gravity," Williams said.

Williams hopes her unique run will inspire young people.

"I encourage kids to start making physical fitness part of their daily lives," Williams said. "I think a big goal like a marathon will help get this message out there."

Due to the ISS crew's sleep schedule, Williams' marathon run on the station may not match exactly with the ground race, but mission control is working to align the events as closely as possible. This year's marathon is Monday, April 16.