Expedition 43 crew members, who will begin their year-long stay at the International Space Station (ISS), have arrived safely at the space outpost.

On Friday, March 27, the Russian spacecraft Soyuz launched from the Baikonur Cosmodrome in Kazakhstan and successfully docked with the ISS.

"The Soyuz TMA-16M vehicle docked to the International Space Station at 9:33 p.m. EDT, over the western coast of Colombia," stated NASA.

The Soyuz spacecraft carried NASA astronaut Scott Kelly and Roscosmos cosmonauts Gennady Padalka and Mikhail Kornienko. Kelly and Kornienko will stay at the ISS for about 12 months then return to Earth in March 2016. Padalka will return to Earth within six months.

Astronauts normally spend about six months or less at the ISS, but the one-year mission will help scientists understand how the human body adapts and reacts to long space journeys. The knowledge will help NASA understand better how to send humans to deep-space missions, including a trip to Mars. NASA suggests that a return spaceflight from the Earth to Mars may take up to 500 days.

Kelly will be the first NASA astronaut to spend about a year in space. Russian cosmonauts have spent about a year or more in space, all on the Mir space station.

The 51-year-old Kelly and 54-year-old Kornienko will undergo many medical experiments during their stay at the ISS. The duo will also prepare the ISS for the estimated arrival of new American commercial crew capsules in 2017. Kelly has not performed any spacewalks, but this journey will allow him to do some spacewalks.

NASA doctors are eager to understand the effect of long spaceflights on humans. Medical experts believe that muscles and bones weaken in zero gravity. Weightlessness also affects the immune system. Body fluids tend to move to the head in zero gravity situations, which may put pressure on an individual's eyes and brain. Astronauts have previously complained of vision problems after returning from space.

While astronauts will definitely undergo physical challenges, they will also have to be emotionally prepared for the year-long trip to space.

The astronauts will look after the cargo ships that will arrive at the station in the next 12 months. Kelly and Kornienko will also take care of Sarah Brightman, the British singer who will visit the ISS as a space tourist.

ⓒ 2021 TECHTIMES.com All rights reserved. Do not reproduce without permission.