The National Aeronautics and Space Administration (NASA) astronaut Scott Kelly has planned to spend about 342 days on the International Space Station (ISS). If Kelly succeeds in his plan, it will be the longest stretch of time any US astronaut has spent in space.

The astronaut lifted off on Friday aboard a Russian Soyuz rocket that was launched from Kazakhstan. As per the United States space agency, the Soyuz rocket docked at the space station at about 9:33 pm.

As per the astronaut's plans, he will stay on the ISS about twice as long as any United States has ever stayed on ISS. Kelly's stay will allow scientists an opportunity to study how a human body can respond to long-duration space flights. On earth, scientists will conduct parallel studies on Scott Kelly's bother Mark Kelly, who is a retired astronaut.

In a media briefing in January, Kelly said that it is fun to be at the ISS as the space station is a magical place. With Kelly, two other cosmonauts, Mikhail Kornienko and Gennady Padalka, lifted off on Friday aboard Soyuz rocket. Padalka will stay on ISS for just six months, while Kornienko will spend one year on the space station.

The three astronauts will join three crew members that are already on the space station. The astronauts who are currently on the ISS are United States astronaut Terry Virts, Russian cosmonaut Anton Shkaplerov and Italian astronaut Samantha Cristoforetti.

If Kelly succeeds to achieve his goal, the 51-year-old astronaut will break the record for the longest mission on the space station. The previous record was set by NASA astronaut Michael Lopez-Alegria and Russian cosmonaut Mikhail Tyurin. They both had spent more than seven months on the space station. They lived there from September 18, 2006 to April 21, 2007.