Over the summer, twin astronauts Scott and Mark Kelly (perhaps unintentionally) offered their identical genetic makeups to science, suggesting that they be the subject of experiments designed to test the effects of space travel on the human body. Next march, Scott will head to International Space Station for a rare year-long stay in outer space. Mark, his twin brother and himself a former astronaut, will remain on Earth, setting up the perfect conditions for controlled genetic experiments involving space travel.

"This is a once-in-a-space-program opportunity," said John Charles, head of NASA's Human Research Program (HRP), at the time. To take full advantage of the offer, NASA requested proposals for "cleverly designed, but limited, short-term investigations for observational comparison between astronaut Scott Kelly and his identical twin brother, retired astronaut Mark Kelly." According to Charles, "in typical investigations, we usually have a specific outcome in mind and are goal-oriented. In this case, the slate is essentially blank." 

Now, as the date for the unprecedented mission nears, details are starting to emerge as to how the experiments will unfold. Mark told the Associated Press yesterday that he won't eat the same foods as his brother. "It's not bad when you're in space," he said, adding that he refuses to carry "a can of Russian lamb and potatoes when I'm out to eat with my friends." He is, however, willing to try to keep up with his brothers exercise regime of 1.5 to 2 hours of activity each day. Scott, for his part, said he's willing to take rather extreme measures for the sake of information: 

Eager to explore new medical territory, Scott offered to have a pressure sensor drilled into his skull to study the impaired vision experienced by some long-term space fliers. He's also volunteered for spinal taps in orbit. He'll share quarters at one point, after all, with an emergency medical doctor-turned-NASA-astronaut. The space station crew typically numbers six.

But NASA has something a little safer in mind. The space agency has allotted $1.5 million towards ten research proposals, each of which will study the twins to see how space travel affects astronauts on a molecular, physiological, and psychological level. Here are the ten proposals that made the cut, and what they hope to find: 

​​Project: "Immunome Changes in Space"

Researcher: Emmanuel Mignot, Stanford University

Purpose: According to the Associated Press, Mignot plans to give each brother a standard flu shot before, during, and after the mission, and look at the differences to see how immunity is affected by space travel. 

Project: Proteomic Assessment of Fluid Shifts and Association with Visual Impairment and Intracranial Pressure in Twin Astronauts 

Researcher: Brinda Randa, University of California

Purpose: Rana is interested in how Kelly's lengthy stay in space will affect his brain fluids and, subsequently, his vision. "Our bodies are adapted to an environment in which gravity pools fluids toward our legs,” she explains, adding, “In space, fluid flows upward. Our project will examine the effects of spaceflight on the proteins that regulate vasoconstriction and dilation, and fluid regulation.”

Project: Differential effects on telomeres and telomerase in twin astronauts associated with spaceflight

Researcher: Susan Bailey, Colorado State University

Purpose: Bailey intends to use blood samples taken from each brother before, during, and after the mission to see how the effects of space travel — especially exposure to radiation, constrained diet, and physical and emotional stress — affect telomeres, which serve as protective ends on our chromosomes. Previous tests have shown that radiation can degrade telomeres. 

Project: Metagenomic Sequencing of the Bacteriome in GI Tract of Twin Astronauts

Researcher: Fred Turek, Northwestern University

Purpose:  According to a Northwestern press release, Turek will study how space travel affects our digestion. This is important because, in more technical terms, "The complex ecological microbiology community that inhabits the human gastrointestinal tract (GI) tract influences normal physiology and behavior and susceptibility to disease," and it's unclear how conditions in space affect microbiota in the intestinal tract. 

Project: Comprehensive whole genome analysis of differential epigenetic effects of space travel on monozygotic twins

Researcher: Andrew Feinberg, Johns Hopkins University School of Medicine 

Purpose: The New York Times reports that Feinberg plans on fully analyzing each brother's genome, and use the discrepancies to determine how space flight changes genes and their functions.

Project: The Landscape of DNA and RNA Methylation Before, During, and After Human Space Travel

Researcher: Christopher Mason, Weill Cornell Medical College of Cornell University

Purpose: Mason hopes to learn how microgravity affects DNA and RNA. Using blood samples taken from the brothers at various intervals throughout the mission, as well as before and after, he and his team will explore "whether gene expression and behavior change while in space. They also will explore whether space travel drives changes between different cells in the body that carry new mutations," per a Weill Cornell press release

Project: Cognition on Monozygotic Twin on Earth

Researcher: Mathias Basner, University of Pennsylvania School of Medicine

Purpose:  Basner and his team will look at how microgravity affects memory, emotions, social cognition, complex reasoning and executive functioning, among other things. 

Project: Longitudinal integrated multi-omics analysis of the biomolecular effects of space travel

Researcher: Michael Snyder, Stanford University

Purpose: Snyder will investigate how space travel affects the biological "omics" – like genomics, proteomics and lipidomics — in the long term. 

Project: Metabolomic And Genomic Markers Of Atherosclerosis As Related To Oxidative Stress, Inflammation, And Vascular Function In Twin Astronauts

Researcher: Stuart Lee, Wyle Laboratories 

Purpose: Lee's project will use the opportunity to study space travel's affect on cardiovascular health. 

Project: Biochemical Profile: Homozygous Twin control for a 12-month Space Flight Exposure

Researcher: Scott Smith, NASA Johnson Space Center

Purpose: Scott Smith is NASA's nutritionist, so he should be perfectly equipped to track Scott Kelly's biochemical profile. A biochemical profile is usually determined using blood tests that show internal organ health.