NASA Twins Study results examining the effects of the human body in a spaceflight environment were published this week in an April 12, 2019 edition of Science. NASA began the study in 2015, with the objective to prepare for advanced crewed missions to the Moon and Mars where maintaining a crew’s health remains the most critical element of a successful expedition. Astronauts in the above image Scott (right) and Mark (left) Kelly, identical twin brothers, participated in the study, with Mark remaining on Earth while his twin Scott spent 340 days aboard the International Space Station. In 2016, Scott Kelly became the first American astronaut to spend almost a year in space, and the brothers’ similar genetics offered researchers a unique opportunity.

NASA’s Human Research Program conducted the study, analyzing the changes that occurred to Scott while in orbit, while comparing his genetics, immune system, and cognitive abilities to his Earth bound sibling. The Twin Study gathered great insight into the need for personalized medicine during long duration deep space missions, along with setting a foundation for future astronaut studies as our civilization’s space programs accelerate into the stars.

Key findings included changes to gene expression, immune system response, and telomere dynamics. Telomeres, contained in white blood cells, indicate biomarkers of aging, and are an important element of cellular genomic stability. Researchers observed Scott Kelly’s telomeres stretching longer in space, though returning to normal length after a period of six months once returning to Earth. Meanwhile, Mark Kelly’s telomeres remained unchanged. This particular finding calls for additional studies for future and longer missions, with the aim of demonstrating repeat results.

During the study, researchers paid additional attention to Scott’s immune system, which responded well when administered a flu vaccine while in orbit that demonstrated the same success as when received on Earth. Researchers also noted broken chromosomes rearranging in chromosomal inversions and changes in cognitive functions. Most of these results remain consistent with previous studies and ongoing research.

Gene integrity and a strong, properly functioning immune system are some of the most important aspects to consider for long term deep space missions.