ASTANA (Kazakhstan) • Three astronauts landed safely in Kazakhstan yesterday, after a 115-day mission aboard the the International Space Station (ISS), including American Kathleen Rubins, the first person to sequence DNA in space.

Russian mission control confirmed the touchdown of Nasa's Rubins, Roscosmos' astronaut Anatoly Ivanishin and Mr Takuya Onishi of the Japan Aerospace Exploration Agency at 0358 GMT.

The trio landed south-east of the Kazakh steppe town of Zhezkazgan in clear but frosty conditions after a flight from the orbital lab.

"Landing has taken place!" Russian mission control stated, with commentators on Nasa TV noting that the Soyuz craft had landed in an upright position.

Molecular biologist Rubins and Mr Onishi were both returning from their first missions in space, while flight commander Ivanishin undertook a five-month mission at the ISS five years ago.

"Everybody is feeling wonderful," said Mr Ivanishin, who emerged first from the craft.

He turned over command of the space station, a US$100 billion (S$139 billion) orbiting research lab, to newly arrived US astronaut Shane Kimbrough.

Mr Kimbrough and Russian cosmonauts Sergey Ryzhikov and Andrey Borisenko reached the outpost on Oct 21. The three astronauts will be on their own until next month, when another three crew members are due to reach the station, a project of 15 nations that orbits about 418km above Earth.

The space laboratory has been orbiting Earth at about 28,000kmh since 1998.

Dr Rubins' just-concluded participation in the mission generated particular excitement after Nasa announced plans for the career scientist to sequence DNA aboard the ISS in a world first.

In August, the biologist successfully sequenced samples of mouse, virus and bacteria DNA using a device called MinION while Earth- based researchers simultaneously sequenced identical samples.

Nasa said the biomolecule sequencer investigation could help to identify potentially dangerous microbes aboard the ISS and diagnose illnesses in space.

Dr Rubins was also the first woman aboard the ISS since Italian Samantha Cristoforetti returned to Earth with the record for the longest single spaceflight by a woman (199 days) in June last year.

AGENCE FRANCE-PRESSE, REUTERS