Indian-origin astronaut Sunita Williams flew to space for the third time on Wednesday along with a colleague, scripting history as the first members aboard Boeing’s Starliner spacecraft on a 25-hour flight to the International Space Station.

Boeing’s Crew Flight Test mission carrying Williams, and Butch Wilmore lifted off from Cape Canaveral Space Force Station in Florida after multiple delays.

Williams, 58, is the pilot for the flight test while Wilmore, 61, is the commander of the mission.

The launch marks the beginning of the NASA-Boeing Starliner Crew Flight Test (CFT), Boeing said.

"This crew flight test represents the beginning of a new era of space exploration as we watch astronauts Wilmore and Williams put Boeing's Starliner through its paces on the way to the International Space Station," said Boeing Defense, Space & Security President and CEO Ted Colbert.

"This is a great start. We look forward to getting the astronauts safely to the space station and back home," Colbert said in a press release.

Wilmore and Williams are also the first to be launched on an Atlas V rocket and are currently experiencing microgravity on their way to the space station. They will conduct a series of flight test objectives, including manually flying Starliner.

Along with the two crew members, Starliner is carrying about 760 pounds (345 kilogrammes) of cargo.

Once docked to the ISS, Wilmore and Williams will spend about a week on station before returning to Earth. Following a successful CFT, Boeing and NASA will continue working to certify Starliner for long-duration operational missions to the ISS.

Williams also made history as the first woman to embark on such a mission. And it won’t be her first entry in the history books.

In 2012, during a prior trip to the International Space Station, Williams became the first person to finish a triathlon in space, during which she simulated swimming using a weight-lifting machine and ran on a treadmill while strapped in by a harness so she wouldn’t float away.

That came after she ran the Boston Marathon from the space station in 2007.

Williams received her commission as an Ensign in the United States Navy from the United States Naval Academy in May 1987. Williams was selected as an astronaut by NASA in 1998 and is a veteran of two space missions, Expeditions 14/15 in 2006 and 32/33 and 2012.

She served as a flight engineer on Expedition 32 and then commander of Expedition 33.

Boeing’s Crew Flight Test mission has been delayed for several years because of setbacks in the spacecraft's development.

Last-minute computer trouble nixed Saturday's launch attempt for Boeing's first astronaut flight, the latest in a string of delays over the years.

It was the second launch attempt. The first try on May 6 was delayed for leak checks and rocket repairs With the launch, Boeing became the second private firm able to provide crew transport to and from the ISS, alongside Elon Musk's SpaceX.