Physiology and Space Travel

Next week will mark the 48th anniversary of the first manned moon landing, conducted by Apollo 11 on July 20th, 1969. It marked a momentous and patriotic moment for the United States, which remains the only country to have successfully accomplished this task, and for the field of aeronautics as a whole. Indeed, “a giant leap for mankind”! (more information about the landing itself here).

Long space missions like Apollo 11 are also a huge physiological feat. Conditions on Earth aren’t the same as they are in space, or on other celestial bodies. Microgravity and radiation effects, just to name two, are really different on the moon than they are here at home. When you go on a mission to Mars, for instance, your body goes through three separate gravity fields. And when you are in the spacecraft, you are exposed to a very contained and unique ecosystem. Scientists back home monitor saliva, urine and blood content to ensure latent viruses, like herpes or Epstein-Barr, are not reactivated. ¬†Astronauts are also subject to about ten times more radiation than normal when they visit the space station, which can have immediate as well as longer term effects on the central nervous system.

As one article published in the Canadian Medical Association Journal sums it up, “astronauts are people with normal physiology who live in an abnormal environment”. Here are some changes the body makes in order to adapt, or acclimatize, to space travel (summarized from this nifty table¬†here):

  • Fluid re-distribution (a temporary in-flight decreased flow to the legs, and increased flow to the head and torso)
  • Neurovestibular effects (the motion sickness astronauts can expect to feel when traveling)
  • Muscle mass changes (mass will decrease up to 30% and will regain/recover post-flight)
  • Bone demineralization (a loss of almost 60-70% in calcium, as well as decreased thyroid activity and Vitamin D production, which recovers upon returning to Earth)
  • Psychosocial effects (Weariness and emotional effects)
  • Immune dysregulation

There are some measures that can be taken to counter these effects, including the following: exercise, negative pressure space suits, anti-nausea medication, resistance training, diet supplements, and exposure to artificial gravity during flight.

Curious to learn more? Here are a few more fascinating reads to get you started from Harvard, the Smithsonian, and StatNews.

Side Note–if you’re a local NC reader, I hope you’ve visited Morehead Planetarium, on UNC’s Chapel Hill campus! Apollo mission astronauts Neil Armstrong, Buzz Aldrin, and Michael Collins all trained here–as well as other space giants.