NASA astronaut Suni Williams will go faster than anyone has ever gone in the Boston Marathon when she runs the famed race in April as an official entrant from 338 km above Earth aboard the International Space Station, NASA announced on Thursday.

This will be the first time an astronaut in space will be an official participant in a marathon. Williams hopes her unique run will serve as an inspiration. "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."

Williams, who is an accomplished marathoner, has served aboard the space station since December 2006 as a member of the Expedition 14 crew. She will run the race on a station treadmill, circling Earth at least twice in the process, running as fast as eight miles (about 13 km) per hour but flying more than five miles (8 km) each second.

And she will not be alone in her adventure. Her sister Dina Pandya and a fellow NASA astronaut, Karen Nyberg, will run the race in Boston. Williams and Nyberg qualified for the Boston race by finishing among the top 100 females in the Houston Marathon in January 2006.

Exercise is essential in NASA's efforts to counteract the effects of long-duration weightlessness on astronauts' health. For months, Williams has been training for the marathon while aboard the station. She runs at least four times a week, two longer runs and two shorter runs. Station crews are required to exercise on the treadmill, a stationary bike and a resistive exercise machine to counter loss of bone density and muscle mass.

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