Washington, Feb 28 (IANS): Three astronauts have landed safely in Kazakhstan on Wednesday after five-and-a-half-month of performing research and spacewalks in low-Earth orbit.

The Soyuz spacecraft with NASA astronauts Mark Vande Hei and Joe Acaba, and cosmonaut Alexander Misurkin of the Russian space agency Roscosmos landed at 8.31 a.m. in Kazakhstan, NASA said.

The three were part of the Expedition 54 crew aboard the International Space Station (ISS).

Vande Hei ventured outside the space station on four spacewalks to perform work that included replacing and lubricating the Latching End Effectors on both ends of the Canadarm2.

Acaba completed one spacewalk to lubricate an end effector and install new cameras on the station's arm and truss. He now has accrued 306 days in space on three flights.

Acaba and Vande Hei also participated in dozens of educational events while in space as part of NASA's Year of Education on Station.

Misurkin conducted one record-setting spacewalk with fellow cosmonaut Anton Shkaplerov to replace an electronics box for a high-gain communications antenna on the Zvezda service module in February.

The spacewalk timed out at eight hours and 13 minutes, the longest in Russian space programme history. Misurkin now has spent 334 days in space on two flights.

Now operating the station are Expedition 55 crew members Commander Anton Shkaplerov of Roscosmos and Flight Engineers Scott Tingle of NASA and Norishige Kanai of the Japan Aerospace Exploration Agency.

Astronauts Ricky Arnold and Drew Feustel of NASA, and Oleg Artemyev of Roscosmos are scheduled to launch on March 21 and arrive at the space station two days later, returning the crew size to six, according to NASA.