Oct 4, 2010 13:41 GMT  ·  By
Astronauts aboard the ISS are getting ready for the arrival of their colleagues, on October 9
   Astronauts aboard the ISS are getting ready for the arrival of their colleagues, on October 9

With half of the crew aboard the International Space Station returning to Earth recently, only three astronauts remained aboard the facility. Now, they are preparing to welcome the rest of the Expedition 25 crew, which is scheduled to arrive in October.

Astronauts that go aboard the station usually spend about six months in weightlessness, conducting experiments, participating in maintenance task, and conducting studies on our planet.

Generally, half of the crew comes or leaves every three months. In other words, the three astronauts that made up the second half of Expedition 24 will also make up the first half of Expedition 25.

After three months as part of this crew, the three will depart the ISS as well, and other astronauts will take their place, marking the start of Expedition 26, and so on.

At this point, aboard the ISS are Expedition 25 Commander Doug Wheeloc, a NASA astronaut, and flight engineers Shannon Walker (NASA) and Fyodor Yurchikhin, from the Russian Federal Space Agency (RosCosmos).

They will be joined soon by flight engineers Scott Kelly (NASA), and Oleg Skripochka and Alexander Kaleri (RosCosmos). They are currently in Baikonur, Kazakhstan, preparing for launch.

Aleksandr Yuriyevich Kaleri is a veteran cosmonaut, having already participated in several long-term stays in space, aboard both the ISS and the Russian-built space station Mir.

He has spent nearly 610 combined days in space, and has a total of 25 hours and 45 minutes of extra-vehicular activities (EVA) under his belt. He will be part of the Expedition 25/26 crew.

Scott Joseph Kelly is at his third spaceflight to the International Space Station. He has already spent nearly 21 combined days into space. Skripochka is at his first flight into space.

At this point, the crew is scheduled to launch from the Baikonur Cosmodrome, in the Kazakh steppes, on October 7. Rendezvous with the ISS is to take place on October 9.

The Soyuz TMA-01M spacecraft that the three astronauts will use to get to space is the first of its kind to use digital control systems, that will guide it as it approaches the space lab.

In anticipation of their colleague's arrival, the three remaining astronauts aboard the ISS have been conducting routine work, and monitoring experiments that are installed on the lab.

At this point, a single Soyuz space capsule remains affixed to the ISS. It will be used by the crew to escape in case anything goes wrong, Space Fellowship reports.