Research on how long term space travel will impact human health will kick into high gear next week as NASA astronaut Scott Kelly comes back to Earth after an 11-month stay at the International Space Station.

NASA Twin Study

As Scott stayed in orbit, he left behind his identical twin brother Mark Kelly, a retired astronaut. By involving the twin brothers, who are genetically identical, in a landmark twin study, NASA can study how long-duration space flight can impact the body and mind with Mark as the control.

"NASA has selected 10 investigations to conduct with identical twin astronauts Scott and Mark Kelly," NASA said. "These investigations will provide broader insight into the subtle effects and changes that may occur in spaceflight as compared to Earth by studying two individuals who have the same genetics, but are in different environments for one year."

Researchers involved in the twin study wanted to know how extended space flight influences, among others, a person's cognition, physiology and microbiome and Scott's soon-to-end ISS mission would provide researchers with a chance to compare several health aspects of the Kellys.

Scott and Mark had their cardiovascular function, visual acuity and other things tested over the past several months. Scott also took blood and urine samples that would be brought back to earth for comparison.

Scott's samples from the ISS have been stored and will arrive on a returning SpaceX capsule about a month following his return.

Preparation For Manned Mars Mission

The twin study aims to help NASA make the necessary preparations for the planned manned mission to planet Mars.

Brinda Rana, a researcher from the UC San Diego School of Medicine, said that by studying how the space environment affects the human body at the molecular level, NASA can identify risk factors and countermeasures to deal with potential health issues that may arise as a result of prolong space travel such as a mission to Mars.

Effects Of Space Travel

Traveling through space is believed to produce possibly adverse side effects on the body due to radiation exposure, microgravity, isolation, elevated carbon dioxide and confinement and a better understanding of these may help NASA make the necessary preparations for longer space travel. A trip to Mars, for instance, may last several months.

 "Our bodies are adapted to a 1g environment in which gravity pulls the blood toward the feet," Rana said. "In space, with nearly zero gravity, the blood and other fluids in the body shift upwards toward the upper body around the heart, the neck and the head. This fluid shift may cause changes in brain pressure and vision, which have been observed in some astronauts.

Medical Applications

Researchers said that knowledge from the twin study may also have medical applications on Earth. The findings, for instance, may shed more light on traumatic brain injury, glaucoma, atherosclerosis and bone loss.

Scott Kelly is set to return to Earth on March 1. His stay at the ISS is the longest an American lived in space.

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