NASA astronaut Scott Kelly is set to launch into space on Friday, while his identical twin brother Mark, will stay on Earth to be observed in a physical experiment to determine the effects of longer space travel duration on the physical human body.
Scott will be spending one whole year onboard NASA's International Space Station.
Mark, who is the husband of former United States Congresswoman Gabby Giffords, will act as a reference for the unique physical experiment.
The twins' body will be compared to each other to note the effects of space on the human physiology. Scott said that the experiment will help determine what needs to be adjusted for future space travelers, according to Sky.
Dr. John Charles, who heads the Human Research Programme at NASA, said that updated medical technology will be utilized to help understand what happens to the human body during an extended period of time for space flight.
While he is in the space station, Scott will be required to undergo several medical tests and experiments.
Scientists are expecting Scott to be taller than Mark when he returns from the space journey. The lower level of gravity in space might temporarily increase Scott's height.
"This time hopefully it will last long enough so that when I get back to the US I can look down at him a little bit," said Scott.
NASA's previous experiments involved astronauts living on the said space station for just half a year. There are already certain problems with prolonged stay in space such as weaker bones and muscles due to the gravity, impaired vision and radiated bodies, according to Chron.
The experiment involving the twins is expected to advance studies that might lead to humans reaching Mars. The Red Planet is currently a subject of interest of Mars One, an organization that aims to establish the first human colony on the planet.