The American astronaut Scott Kelly and his Russian counterpart Mikhail Kornienko have blasted off to begin a year away from Earth.

Gennady Padalka of Russia is also riding in the Soyuz spacecraft; he is scheduled for the standard six-month tour of duty aboard the International Space Station.

The trip is Nasa’s first stab at a one-year spaceflight, will feature experiments necessary to plan for a manned mission to Mars that would last two to three years.

The Soyuz set off from Russia’s manned space launch facility on the steppes of Kazakhstan and was due to dock with the space station hours later.

Kelly’s identical twin Mark, a retired astronaut, agreed to take part in many of the same medical experiments as his orbiting sibling to help scientists see how a body in space compares with its genetic double on Earth.

Mark is the husband of former congresswoman Gabrielle Giffords, who was shot and seriously injured in 2011.



Kelly, 51, and Kornienko, 54, took off from Baikonur, Kazakhstan, one of the oldest launch facilities on Earth.

Kelly will be the first American to spend a continuous year in space; Russian Valeri Polyakov spent more than a year on the Mir space station in the 1990s.

During their year-long mission, 12 other astronauts will join them for shorter stints – including Padalka, a Russian who has spent more than 700 non-consecutive days in space. After this trip Padalka he will have spent more days in space than any other human being.

More than 40 years after Americans landed on the moon, many in the US consider spaceflight relatively routine, but its dangers remain as destructive to human beings as ever, and sometimes as mysterious: eyeballs distended by brain fluid floating weightless around the skull, pathogens made more virulent by the variables of space, bone loss, muscle atrophy, radiation.

During their year on the ISS, Kelly and Kornienko will perform daily cognitive, visual, physical, microbial and metabolic tests, and will also keep journals that will help their respective space agencies study the psychological toll of a year in orbit.

“Imagine if you went to work where your office was and then you had to stay in that place for a year and not go outside, right? Kind of a challenge,” Mark Kelly, Scott’s twin, told the Associated Press.

The mission also has major implications for plans for future deep-space missions, which would require lengthy exposure to radiation, weightlessness and the many vagaries of life in space.

“We know a lot about six months, but we know almost nothing about what happens between six and 12 months in space,” Julie Robinson, a Nasa scientist, said during a press conference earlier this year.

A mission to Mars would likely take almost three years, accounting for 12 months of travel and around 18 months on the planet or waiting for an opportunity for it to realign with Earth. Average Nasa missions last several weeks to six months, and require astronauts, already peak performers, to keep in top physical and mental condition to stay healthy under the duress of space.

Back on Earth, Kelly’s identical twin brother Mark will also meet with former colleagues at Nasa for the mission.

Although Kelly was not selected for this mission because he and his brother are twins, the Kellys’ nearly identical genetic code presents a special opportunity to study how space affects humans with a virtual DNA control case on the ground.

Eyesight problems and kidney stones – the latter likely due to the intense carbon dioxide in the space station’s air, at 10 to 20 times that on Earth – are also major concerns for long space missions, and Nasa hopes the Kelly twins can provide a case study to begin parsing the causes of such persistent astronaut conditions.

An astronaut’s health has major consequences on a mission beyond his or her role on the station: in the delicate, high-stress environment, a small mistake could have catastrophic consequences – fire or equipment failure, for example. A health condition like pressure on the brain displaced by weightlessness increases the chances of that kind of error.

Kelly and Kornienko, already experienced with several trips to the ISS, have trained rigorously for the trip. Both have said they worry most about the emotional strain of such a long trip away from home and family. In addition to his well-known brother and sister-in-law, Kelly has two daughters and a girlfriend whom he will be able to periodically call via a choppy connection; Kornienko has a wife, daughter and young granddaughter.

In the downtime between their busy schedules of experiments, exercise and maintenance, they will also be able to escape into their respective private spaces, each about the size of a phone booth. The station is roughly the size of a three- or four-storey building, or a little larger than a football field, and is divided between zones for Russian and American astronauts.