We've dedicated many articles to how stem cells react in a person's body or a Petri dish on Earth. But what happens to a person's cells when they're orbiting the Earth thousands of miles away? 

By now, peoples' bodies have adjusted to the Earth's atmospheric conditions. They've developed over thousands of years in an environment regulated by gravity. But when someone travels to space these same conditions don't exist for the most part.

Take for example Scott Kelly, the first American astronaut to spend a year in space. Prior to his launch, scientists were likely working around the clock to determine exactly how his body would hold up and change during his tenure. The types of transformations would depend on where he was traveling. For example, traveling to Mars could have a different affect on the body than if someone was making a stop at the moon.

Today, scientists outside of NASA are continuing their study of human cells – specifically ones in the cardiovascular system – outside of Earth's atmosphere.

How are scientists studying cells with no gravity?
This past July, one team of scientists, led by Arun Sharma from Stanford University in Palo Alto, California, turned adult blood and skin cells from three people into a certain type of stem cell, according to Science magazine. From there, SpaceX CRS-9 carried these cells to the International Space Station, and left them there for a month. Once the cells returned to Earth, scientists compared them to a control set that was placed in conditions not devoid of gravity.

Scientists have found, so far, that the cells traveling to space developed a faintly irregular rhythm compared to those on Earth. In fact, when the cells in space returned to Earth, their rhythm went back to normal.

Mary Kearns-Jonker of Loma Linda University in California, in a separate study, conducted a similar experiment, but did so in a clinostat, which is a device that constantly spin cells to reduce gravitational force.

Her results indicated that cells under microgravity can go through a process called dedifferentiation, which involves losing a particular specialization and reverting back to a more simplified state of being. The results also showed that microgravity can induce certain genes to form when damaged tissue regenerates.

Kearns-Jonker also has plans to send cells into space to see whether age-dependent effects she noticed on Earth happen in space too.

What's the end goal?
It's critical that NASA and other scientists do everything they can to assist people traveling to outer space because protecting the body from extreme conditions is paramount. Abba Zubair, a stem cell researcher at the Mayo Clinic, thinks that one day astronauts could grow stem cells from the ISS.

However, beyond space travel, Sharma noted these studies could help scientists better understand the aging process, and Kearns-Jonker has plans to potentially look into the healing affects of progenitor cells.