A Balancing Act: How Months in Space Impact Astronauts' Performance

Billy Hurley, Digital Editorial Manager

When you arrive back on Earth after a year in space, you’re going to feel it.

NASA and Jacob Bloomberg, senior scientist in the Houston, TX- headquartered Johnson Space Center, have been trying to quantify exactly what those effects will be — and how 12 months of microgravity impact an astronaut’s ability to perform simple operational tasks like opening a hatch or climbing a ladder.

Leading a Functional Task Test , Bloomberg’s team discovered that an International Space Station (ISS) crew had the greatest difficulties with performing duties requiring postural control, stability, and muscle dexterity. In other words, life after weightlessness is a balancing act.

Time in Space

As part of NASA’s One-Year Mission , American Astronaut Scott Kelley spent a year on the International Space Station (ISS) with Russian Cosmonaut Mikhail Kornienko.

The mission, part of NASA’s Human Research Program , seeks to understand how spaceflight changes an astronaut’s physiological systems and functional performance as the human body adjusts to microgravity, isolation, radiation, and the stress of spaceflight.

During long-term missions, microgravity exposure causes astronauts to experience physiological transformations, including sensorimotor disturbances and cardiovascular deconditioning, or a loss of muscle mass and strength.

NASA Astronaut Scott Kelly points and drags on an iPad as he performs the One-Year Mission's Fine Motor Skills Test. (Credit: NASA)

For missions to asteroids or other planets, Bloomberg and NASA want to know how spaceflight’s physiological effects could impair an astronaut’s ability to perform assignments immediately following the landing on a planetary surface like Mars.

The Test

The Functional Task Test connects changes in physiological systems like brain, cardiovascular, and muscle function to functional performance in actions like obstacle avoidance, climbing, and turning the wheel of a hatch. Astronauts are assessed before spaceflight and after their return to Earth.

Upon his arrival home, Kelly, for example, performed a Fine Motor Skills Test, part of which included simple actions on an Apple iPad.

By placing the returning astronauts through the tests, Bloomberg determined that a certain kind of task unsteadied those aboard the International Space Station.

“Similar to the results observed in a six-month mission, the One-Year Mission showed us that tasks that required balance control showed the greatest decrease in performance,” said Bloomberg in this NASA video .

The most challenging actions, according to the NASA study, required postural stability: recovering from a fall, carrying an object, or avoiding an obstacle while walking, for example. Conversely, jobs not requiring balance control, such as the manipulation of objects and tools, showed little reduction in performance.

According to Johnson’s senior scientist, the Human Research Program findings demonstrated that astronauts will need to work out new ways of regaining strength and addressing the loss in balance. Technologies like NASA’s Advanced Resistive Exercise Device, for example, allow an ISS user to perform three resistive workouts that stimulate bone regeneration and exercise the major muscle groups.

“These results point to the importance of developing exercise programs for astronauts that in addition to maintaining muscle and cardiovascular function also keep the brain’s balance system tuned for standing and walking, improving the ability of astronauts to explore new worlds on future missions,” said Bloomberg.

To provide counterbalance training, NASA has also developed a Sensorimotor Adaptability Training System. With a treadmill mounted on a motion base, subjects are exposed to different combinations of support surface movement. Like a flight simulator, visual scene motion allows a user to practice dealing with challenging and conflicting sensory information.