Three new crew members have joined the International Space Station, including a US grandfather who is poised to enter the record books during his time there, NASA said.
The Russian spacecraft carrying the astronauts docked at 0309 GMT Saturday some 407 kilometers (253 miles) above the Pacific Ocean, off the western coast of Peru, according to the American space agency.
Just over two hours later, crewmates Oleg Skripochka and Alexey Ovchinin of Russia, plus Jeff Williams, a US grandfather of three who is a veteran of long-duration space missions, floated into the orbital outpost after hatches were opened to allow their entry.
"Welcome to @Space_Station! Hatches are opened and the crew onboard grows from 3 to 6 members," NASA tweeted.
According to NASA, the trio orbited the earth four times in their approximately six-hour journey to the ISS.
"Can't believe we just left the planet and we're here already," said Williams, in a call to friends and family gathered back on Earth, which was broadcast online by NASA TV.
By the end of his half-year trip aboard the ISS, Williams "will become the American with the most cumulative days in space—534," NASA said.
Williams is also now the first American to be a three-time, long-term ISS resident, the US agency said.
The rocket took off in windy conditions from Russia's space base in Kazakhstan at 2126 GMT Friday.
The craft is decorated with a portrait of the first man in space, Soviet hero Yuri Gagarin, whose pioneering orbital flight was made nearly 55 years ago, on April 12 1961.
Williams to break Kelly record
The previous US record for most cumulative days in space was set by astronaut Scott Kelly earlier this year.
Kelly, 52, spent nearly a year in space and returned to Earth earlier this month with a total of 520 days in space, as part of an experiment to test the effects of long-duration spaceflight on the body and mind ahead of a potential future mission to Mars.
The all-time record for cumulative days spent in space is held by Russian cosmonaut Gennady Padalka, who racked up 879 days over his career and wrapped up his final mission in September 2015.
Before arriving at the space station, Williams had notched up over 362 days in space, including three spacewalks.
His previous missions were flown aboard the space shuttle Atlantis in 2000, as well as a trip in 2006 when the station was far smaller—with only two modules and three crew members.
In 2009 and 2010, Williams served as a flight engineer for three months and later commanded the ISS for the remainder of his half-year mission.
Williams, Skripochka and Ovchinin joined US astronaut Tim Kopra, Russian cosmonaut Yuri Malenchenko and the European Space Agency's British astronaut Tim Peake at the ISS to continue Expedition 47.
Over five months the crew will conduct more than 250 science investigations in fields ranging from biology to technology development, NASA said.
Among these will be a test of the effects of a large fire in space, carried out by setting off a blaze inside an orbiting unmanned space craft.
The astronauts will also study how soil behaves in microgravity and test a gripping device for use in harsh space conditions that was inspired by geckos.
The ISS has been orbiting the Earth at roughly 28,000 kilometres (17,400 miles) per hour since 1998 and has been continuously occupied since the first expedition in November 2000.
Space is one of few areas of cooperation between Moscow and the West that has not been disrupted by tensions connected to violence and separatism in Ukraine.
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