A Mirror In Outer Space

A first time ever experiment is occurring later this year on the international space station. In the coming years, humanity hopes to embark on journeys reaching further into space than ever before - eventually hoping to send individuals on a manned mission to Mars. Before they can do this, however, more must be understood about how exactly the human body functions in space, and what adverse effects life in microgravity have on the human body. Later this year, astronaut Scott Kelly will embark on the first ever year long mission aboard the International Space Station, which will be the longest continuous time that anyone has spent in space. Kelly will be performing other duties while on this mission, but the mission's main focus will be studying the effects of long term residence in a microgravity environment. Conveniently, Kelly has a twin brother (who is also an astronaut) who will be monitored on earth during Kelly's stellar excursion, providing a control for the experiment, and hopefully allowing researchers to ascertain a deeper understanding of physiology in space.

Astronaut twins Scott (on the left) and Mike Kelly. 

Thanks to evolution, the human body is pretty well adapted to living on earth. Most of our physiology is based upon being pulled down on by a force of 9.8 m/s/s, and once you remove this force, strange things begin to happen. The biggest effect is felt in the astronaut's lower body, as this part (which has spent its entire existence supporting something) suddenly doesn't have anything to do. The load bearing bones (the legs, hips, and spine) begin to break down, releasing calcium into the body (doctors call this phenomena spaceflight osteopenia). This causes the bones to become more brittle, increasing the chance of a fracture. The release of calcium into the astronauts system can also increase the likelihood of kidney stones. This reduction occurs at a frightening rate, up to 1.5% of load bearing bone mass lost per month.

Alongside bone loss, astronauts also experience some degree of muscle atrophy. Much like the load bearing bones, the muscles in ones back and legs experience a reduction in use, which results in their weakening; without proper exercise, astronauts can lose up to 20% of their muscle mass in 5 to 11 days. Up until now, astronauts have bungie corded themselves to a treadmill, used a stationary bike, or have used a device called ARED (which simulates weightlifting) to help stave this off, but research is still being done to improve interstellar fitness.

Body Fluid changes in Outer Space

Another physiological challenge that astronauts face in microgravity occurs within their fluid systems. Gravity plays a huge part in how our bodies manage fluids. Once an astronaut enters a microgravity environment, his or her fluids (which are no longer being pulled down by gravity) being to congregate in the upper body, resulting in symptoms that resemble the common cold. Plasma volume (the water in the blood stream) can decrease up to 20%, which can result in something called Orthostatic intolerance, which is the loss of the ability to stand without help for more than 10 minutes at a time. This effect is exacerbated with longer stays in space, but so far no astronaut has failed to recover once they have returned to Earth. A reduction in body fluids puts less stress on the heart than would normally occur, which causes the heart to atrophy as well, which lowers blood pressure. This can cause complications once the astronaut returns to a gravitational environment. Shifting fluids also result in an increase in intracranial pressure. This in turn puts pressure on the optic nerve, which can cause vision problems in astronauts.

Why is all of this stuff such a big deal? Currently, we want to send people to Mars, a journey which will take six months with today's technology. Since there aren't any hospitals on Mars, anyone who goes there will have to be in a condition in which they'd be able to survive the harsh conditions of a foreign planet, which is something that hasn't quite been figured out. Hopefully NASA will be able to gain some important insights from the Kelly mission that will allow a better insight into how to treat space adaptation syndrome.

Posted by David Almanzar (Group A)