Two identical twin American astronauts will aid in the study of the long-term effects of spaceflight and weightlessness. Mark Kelly will remain Earth-bound as his twin brother Scott Kelly heads to the International Space Station for a one-year stay, Reuters reports. Mark Kelly left NASA in 2011 after his wife Gabrielle Giffords, a former US representative, was shot.
"This opportunity originated at the initiative of the twin astronauts themselves," NASA says in its solicitation for research proposals.
By studying the brothers, NASA will examine how genetics affects health problems associated with spaceflight, such as bone loss and vision problems. NASA adds that it plans to collect blood samples from the twins at regular intervals, as well as some limited saliva, cheek swab, and stool samples.
In its request for proposals, NASA notes that it is looking for "limited, short-term investigations examining the differences in genetic, proteomic, metabolomics, and related functions in twin male monozygous astronauts associated with differential exposure to spaceflight conditions. "
Of course, as the New Scientist points out, this is a tiny sample size, and Mark Kelly has been exposed to the effects of space as he has spent 54 days in orbit. "Ideally one would never have flown, but that's not the hand we were given," says John Charles, the head of NASA's human research program. "The only twins we have access to are both astronauts."
Proposals are due September 17.