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September 13, 2019 Keeren Flora By Keeren Flora My Articles

Why We Haven’t Been To Mars Yet | Space Food Technology

Going to space is a major undertaking and takes its toll on the body. Nutrition is just one area that can counteract some of the negative effects.

If food scientists can find just the right diet to sustain astronauts, this could be the key to unlocking longer space exploration missions, like the much talked about 3-year journey to Mars (estimated for 2030).1

Astronauts on the International Space Station (ISS) spend about 6 months living and working in space.2 NASA researchers have studied the way the body is affected in this environment, and they have found that nutrition is a big factor in solving some of the issues.3

Microgravity makes astronauts weaker

Astronauts definitely make floating around in their spacecraft look fun. Microgravity, or being weightless, changes the way you use your body. Without the resistance created by gravity, the body is not as active as it is on Earth. For example, when you walk your leg muscles work to push against the ground, as gravity has created a resistance force on your body. However, in microgravity, it doesn’t take much effort to move around, and the result is weaker muscles and bones. In fact, microgravity has such a significant effect on the body, scientists comparatively study people who are subject to weeks of bedrest in order to investigate the similar impacts of being in space.4

So, what does this have to do with what astronauts eat? A major impact of space flight is on bones—when there is little gravitational resistance acting on bones, they start to weaken and lose minerals like calcium. The result is brittle bones, a condition comparable with osteoporosis. But with an increased level of calcium in the diet, along with exercise, astronauts can start to replenish their bones. Scientists are still researching the right amount of calcium that will keep astronauts’ bones healthy for longer space flights.4

How astronauts get vitamin D

There is another missing nutrient that bones need: Vitamin D. Earth’s atmosphere and magnetic field filters out harmful radiation that can cause cancer. In space, there is no such protections from radiation, plus astronauts are more exposed to more harmful cosmic rays and solar radiation.5 So the space station walls must block all of this radiation, including light. With no natural sunlight, vitamin D cannot be produced in the skin, so all of the astronauts’ Vitamin D requirements must be taken in through the diet. A lack of vitamin D has many impacts, as without it, calcium cannot be absorbed to strengthen bones.6

Fun Fact: On the ISS, each crew member exercises for about 2 hours per day.7 They use a treadmill where they are attached with a bungee cord, a stationary bicycle and specially designed weightlifting machine.8

Getting enough calories in outer space

In the past, it was common for astronauts to lose weight when they go to space. On earlier space missions and early ISS missions, a lack of time to eat, bad sleep patterns and stress are thought to have contributed to the astronauts’ lack of appetite.9 On the most recent ISS missions, astronauts have eaten enough to meet their energy requirements, whereas on previous missions they only met 80% of the requirement.10 The ISS astronauts occasionally complain that the food is still not palatable enough. It is also thought that fluid shifts and congestion (caused by the first days of microgravity) affect taste buds and the olfactory system (sense of smell). On top of that, motion sickness is going to occasionally prevent astronauts from eating well.

Fun Fact (or should we say gross fact?): Carbonated drinks have fallen out of favour with astronauts. Without gravity to separate the gas from liquid in the stomach, burping results in a little vomit coming up as well. The phenomenon is called ‘wet burping’.11

Antioxidant-rich foods protect against radiation  

Even within the considerable shielding of the spacecraft, harmful radiation still reaches the crew. The low wavelength radiation, such as gamma rays, can split water and generate free radicals. When this happens in the human body, the result is an increased risk of cancer. Although the body has some defences against oxidation (caused by free radicals), supplements are added to the astronauts diet, like higher levels of vitamins C, E and A, as well as minerals such as copper, manganese and zinc.4

Fun Fact: Did you know there are more than 4,000 foods that contain antioxidants?  For example, mangos and carrots contain beta-carotine; milk, nuts and shellfish contain zinc; and dark chocolate contains polyphenols.4

There is still much work to be done to perfect the astronaut’s diet, but even when scientists do create a balanced astronaut diet, how will they get enough food on the spacecraft to last 3 years? Learn about it in this article.

If you had the opportunity, would you go to space? Let us know in the comments below!

September 13, 2019 Keeren Flora By Keeren Flora My Articles


  1. “Nasa's journey to Mars.” NASA. Accessed 8th July 2019.
  2. “Astronauts answer student questions.” NASA. Accessed 23rd July 2019.
  3. Smith, S. M., Davis-Street, J., Neasbitt, L., Zwart, S. R. (2012) “Space Nutrition.” National Aeronautics and Space Administration. Accessed 8th July 2019.
  4. Smith, S. M., Zwart, S. R., Heer, M. (2014) “Human Adaption to Spaceflight: The Role of Nutrition” Accessed 8th July 2019.
  5. “Scientists aim to protect Astronauts from deadly spacce radiation.” Newsweek. Accessed 23rd July 2019.
  6. Smith, S. M., Heer, M. A., Shackelford, L. C., Sibonga, J. D., Ploutz-Snyder, L., Zwart, S. R. (2012) “Benefits for bone from resistance exercise and nutrition in long-duration spaceflight: Evidence from biochemistry and densitometry.” Accessed 8th July
  7. “International Space Station crew timeline. 2008” NASA. Accessed 8th July 2019.
  8. Schneider, S. M., Amonette, W. E., Blazine, K., Bentley, J., Lee, S. M., Loehr, J. A., Moore, A., D. Jnr., Rapley, M., Mulder, E. R., Smith, S. M. (2003) “Training with the International Space Station interim resistive exercise device.” Accessed 8th Jul
  9. Nicogossian, A. E., Williams, R. S., Huntoon, C. L., Doarn, C. R., Polk, J. D., Schneider V. S. (2016) “Space Physiology and Medicine: From Evidence to Practice” Accessed 8th July 2019.
  10. Perchonok, M., Douglas, G., Cooper, M. (2012) “Risk of Performance Decrement and Crew Illness due to an Inadequate Food System” Accessed 8th July 2019.
  11. “Field Journal: Eating on the ISS” (2001) Kloeris, V. Accessed 8th July 2019.