Medical Challenges of Space Travel

Medical Challenges of Space Travel
NASA Kennedy Space Center

Space exploration presents many challenges, but the medical challenges of space travel may dwarf the technical challenges. Spending lengthy sojourns on the International Space Station (ISS) has already shown some of the problems that future space travelers will face.

One problem astronauts face is space anemia caused by a lack of red blood cells. On Earth, the human body makes two million red blood cells every second to replace the ones that are lost. In space, the astronauts’ bodies lose three million red blood cells each second, and they must replace those cells. Anemia results from a shortage of the red blood cells needed to carry oxygen to all parts of the body. It causes fatigue, dizziness, and weakness.

Space anemia was well-known, but scientists thought the body would adapt and correct the problem after an extended time in space. Unfortunately, a recent study of 13 astronauts has shown that it is not corrected after six months on the ISS. Furthermore, it took three to four months to restore a near-normal red blood count after the astronauts returned to Earth. There was still a thirty percent greater loss of red blood cells even after that.

A new study on cosmonauts in the ISS shows another area of concern. Scientists studied the brains of twelve cosmonauts just before and after their space flights and again seven months after they returned to Earth. They used computer reconstruction of data from magnetic resonance imaging (MRI) to study the structure (gray matter) and connectivity (white matter) in the brain. The research showed shape changes in the brain, especially in the corpus callosum, a large bundle of nerve fibers that connect the brain’s two hemispheres. In addition, researchers detected “changes in the neural connections between several motor areas of the brain.” But, perhaps, the most concerning is that in the brain scans taken seven months after the cosmonauts returned to Earth, the changes to the brain were still present.

A journey to Mars and back will take more than twenty months. During that space flight, astronauts will need protection from radiation, food for proper nourishment, and to replenish red blood cells while they experience “rewiring” of their brains. The many medical challenges of space travel remind us how blessed we are that God has given us the perfect planet to call home.

— Roland Earnst © 2022

References: and Frontiers In Neural Circuits