October 29, 2015 – Expedition 45 Commander Scott Kelly has been in space more consecutive days than any other NASA astronaut. Today he exceeds Michael Lopez-Alegria’s record of 215 days on a single spaceflight. He also passed Michael Fincke’s record of 382 cumulative days in space on October 16.
Breaking these types of records for time in space is important because every additional day helps scientists better understand how long-duration spaceflight affects bodies and minds, which is critical to advancing NASA’s journey to Mars.
Scott began his year-long mission on the International Space Station in March 2015, while his identical twin brother, retired astronaut Mark Kelly, remains on Earth as an experimental control. As the only set of twins that have ever been to space, the two brothers are providing an unprecedented opportunity for scientists to better understand the effects of spaceflight on the human body.
NASA selected ten separate investigations that focus in part on the comparison of blood samples collected from Scott and Mark at regular intervals before, during and after the one-year mission. Physiological and psychological testing are also being conducted on the brothers to isolate any changes that can be attributed to life in space.
Colorado State University (CSU) researcher Susan Bailey is among the hand-picked scientists chosen by NASA’s Human Research Program to coordinate and share data and analysis from the investigation as part of an integrated research team.
In the CSU project, the first study of its kind, Bailey is studying changes to the the twins’ chromosomes in blood samples. Each chromosome has a protective end-cap called a telomere, which Bailey compares to the plastic tip on a shoelace that keeps the lace from unraveling. As cells divide and replicate during the course of human life, the chromosomes divide as well, and the telomeres gradually erode, eventually leading to the natural death of cells.
For the NASA project, Bailey gathered baseline data on the twins’ telomeres and is now examining how the various demands of life in space – like exposure to radiation, limited diet, and physical and psychological stress – affects those caps on Scott’s chromosomes.
Although the investigations conducted on the Kelly brothers are not expected to provide definitive data about the effects of spaceflight on individuals – because there are only two subjects for data collection – they could help scientists separate the nature vs. nurture effects of spaceflight on the human body and also determine specific areas that need to be addressed before humans journey into deep space.
Kelly is scheduled to return to Earth on March 3, 2016, by which time he will have compiled 522 total days living in space during four missions.