Kelly Twins Perfect Subjects for Astronaut Study

Erik Schechter | NASA Special Edition

So far, it’s been a long battery of tests — ultrasounds, cognitive experiments and assorted, ahem, sample collections — for Mark Kelly, a former NASA shuttle commander and husband of former congresswoman Gabrielle Giffords.

“A team of people recently came out to Tucson to gather some ‘data,’ which consisted of about 30 tubes of blood and other bodily fluids. I tweeted a picture of it,” Kelly said.

At the same time, his identical twin brother, Scott, an astronaut currently aboard the International Space Station (ISS), has been undergoing similar tests, but in zero gravity. “The urine collection experience can be quite complex and takes some practice to get right,” Scott Kelly explained by email from the ISS. “We put those and other samples in a -98 degree (Celsius) freezer for return to Earth at a later time.”

Some of these samples will come back on a SpaceX cargo craft. Others will arrive on Earth via a Russian Soyuz capsule. In the meantime, Scott and Mark have more tests to take.

One Year in Space

NASA’s Human Research Program at the Johnson Space Center in Houston officially began its 10-part study of the Kelly twins on March 27 when Scott was launched into space aboard a Soyuz.

The aim of the Twins Study, which includes teams from more than a dozen universities, labs, hospitals companies, institutions and agencies, is to better understand the health risks of an extended stay in space in order to prepare for a Mars mission.

Scott is expected be on the ISS for 342 days. That’s not a perfect analogue to a Mars mission, which would be a 12-month round trip plus the extra months spent on the surface of the planet, but it’s longer than any other NASA test subject has been in space.

And on Earth, Mark makes the perfect control subject, providing a point of comparison to whatever physical effects Scott experiences.

Kidney Stones and Broken Bones

One of the 10 studies addresses nutrition, which can make or break a mission. “Scurvy killed more sailors (in the days of the explorers) than all other causes combined,” said Scott Smith, lead scientist at the Johnson Space Center’s Nutritional Biochemistry Lab.

In addition, Smith’s team will review before-and-after X-rays of the twins and look for specific bone markers in Scott’s blood and urine to understand what happens to the human skeleton in space. Bone breakdown in zero-gravity has been documented in the past, but no one knows when the deterioration levels off. “This is our first step beyond six-month flights,” Smith said.

Fragile bones can lead to broken bones, which can compromise a mission. Calcium released from bones can also lead to painful kidney stones, and if that happens in space, “you better pray really hard that it is small and it passes quickly,” Smith said.

Deformed Eyeballs and Vision Problems

NASA has long recognized that space travel affects vision. “Astronauts would carry a couple of extra pairs of glasses with them to adjust their vision as needed,” noted Michael Stenger, a Wyle Science, Technology and Engineering Group researcher who is a principal investigator on NASA’s Fluid Shifts investigation.

But, he added, after short shuttle missions, those problems typically resolve themselves.

Then came the six-month missions aboard ISS. Some of the astronauts on those crews found their vision didn’t return to normal back on Earth. Instead, their eyes deformed, and the optic nerve was distended and swollen, leading to poorer vision and even “cotton wool spots” — fluffy white lesions on the retina that typically fade with time on Earth.

The question becomes: What would happen on an extended mission to Mars?

“When you get to three years (living) in space, we don’t know how bad this can get,” said Stuart Lee, lead scientist at NASA’s Cardiovascular Laboratory and also a Wyle researcher.

Chromosomal Damage

Another concern being addressed in the Twins Study is the possibility of accelerated aging, cardiovascular disease and cancer due to chromosomal damage.

Susan Bailey, an associate professor of environmental and radiology health sciences at Colorado State University, leads the team that studies what happens to an astronaut’s telomeres (the long protective caps on the ends of chromosomes) and telomerase (the enzyme that maintains telomere length) after being exposed to the stresses of an extended stay in space.

Telomeres are measured by taking cells from room-temperature blood samples and placing them under a microscope. A fluorescent probe is then put on the cell, lighting up the telomeres. “The brighter the fluorescent signal, the longer the telomere,” Bailey said.