MOSCOW - U.S. astronaut Frank Rubio, who broke the record for the longest continuous spaceflight by an American, and two Russian cosmonauts began their journey back to Earth on Wednesday from the International Space Station (ISS), six months late.

The Soyuz MS-23 undocked from the ISS a minute earlier than scheduled. It will shoot around Earth in orbit and then blast downwards into the Earth's atmosphere at 10:55 GMT, said Roscosmos, Russia's space corporation.

"The undocking has taken place," Moscow mission control said.

Rubio, who is 47 and on his first space voyage, is travelling back to Earth with Russian cosmonauts Sergey Prokopyev, 48, and Dmitry Petelin, 40.

Shortly after entering the atmosphere, it will unfurl a parachute and is due to land in the grassland steppe of Kazakhstan, around 148 km (91 miles) southeast of the city of Zhezqazghan, at 11:17 GMT.

They are six months late to return because their original spacecraft sprang a leak so a replacement had to be sent up to get them back. That gave the two Russians and Rubio an unexpectedly extended mission of 371 days in orbit.

On Sept. 11, Rubio surpassed the previous NASA record of 355 consecutive days in space set by now-retired U.S. astronaut Mark Vande Hei. Rubio is also the first American to spend a full year in space.

Though Rubio broke the American record, he and his Russian colleagues are far from the Russian record.

Valeri Polyakov, a Russian, holds the world record for the longest space journey ever - 437 consecutive days and 18 hours during a Mir space station mission between January 1994 and March 1995. Polyakov died last September aged 80.

(Reporting by Guy Faulconbridge in Moscow and Steve Gorman in Los Angeles; Editing by Mark Trevelyan and Gareth Jones)