Three U. S. and Russian astronauts concluded a 5 1/2 month stay aboard the International Space Station late Tuesday, as their Soyuz capsule descended safely to Earth, touching down under parachute in Kazakhstan.

NASA Astronaut Chris Cassidy, left, and Russian Cosmonaut Pavel Vinogradov share a laugh after 166 days in space. Photo Credit/NASA TV.

NASA astronaut Chris Cassidy and cosmonauts Pavel Vinogradov and Alexander Misurkin were assisted from their capsule within minutes of landing under mostly sunny skies at 10:58 p.m., EDT, or on Wednesday at  8:58 a.m., local time, by recovery teams flown by helicopter to the landing site southeast of Dzhezkagan.

Before they departed the landing site by helicopters, Cassidy and Misurkin retreated to a medical field tent, where they participated in simple exercises to help medical experts assess what human explorers might be able to accomplish on the surface of another planetary body after spending months in weightlessness aboard an interplanetary spacecraft.

“The question is: ‘What is their condition? What could we expect them to do?'” explained Mike Suffredini, NASA’s International Space Station program manager. “And it will kind of lead our thinking on how the first few days of any exploration mission would take place to make sure the crew doesn’t hurt themselves in the process of landing and getting themselves ready to operate on the surface of a foreign planet.”

Cassidy and Misurkin were asked to sit and stand up and walk heel to toe for a short distance in the privacy of the field tent, according to NASA spokesman Rob Navias, who was at the landing site.

All three fliers appeared to be in good spirits, perhaps all the more so by the balmy weather that greeted them. The forecast called for the possibility of rain.

As they descended, one of the former space station astronauts said he looked forward to coffee and apples.

The three fliers were to be flown by helicopters from their landing site to Karaganda in Kazakhstan. Cassidy was to join NASA officials who traveled to the landing aboard a space agency jet transport for a flight back to Houston in the United States.  Another plane was to fly Vinogradov and Misurkin to Star City near Moscow.

The trio became the first astronauts to launch from the Baikonur Cosmodrome in Kazakhstan and dock with the space station within six hours, or four orbits of the Earth, The express mission offers an alternative to the traditional practice of launching then taking more than two days to make the journey in the cramped Soyuz.

While on the station, Cassidy, Vinogradov and Misurkin tended or participated in dozens of medical and biology experiments; technology demonstrations; Earth observations and educational activities. They greeted unpiloted re-supply capsules from Europe, Russia and Japan and participated in three spacewalks.

Command of the station transferred to Fyodor Yurchikhin and the first members of his Expedition 37 crew, U.  S. astronaut Karen Nyberg and European Space Agency astronaut Luca Parmitano. They’ve been living and working aboard the station since late May.

They are to be joined in late September by new Expedition 37 crew members, U. S. astronaut Mike Hopkins and cosmonauts Oleg Kotov and Sergey Ryazanskiy.

Their launching aboard another Soyuz crew transport is scheduled for Sept. 25.