Above: Mars-manned-mission vehicle (NASA Human Exploration of Mars Design Reference Architecture 5.0)

Have you ever dreamed of being an astronaut and going into outer space? If you could, where would you go? Right now, the main destination for astronauts from around the world is the International Space Station (ISS), which is currently home to six people who orbit the Earth about 16 times a day. However, there has been a lot of discussion about exploring deeper into space. Some have proposed building a permanent base on the Moon, while others want to put a space station close to the Moon, visit an asteroid, or eventually land on Mars. But if these dreams are to become a reality, two key issues need to be addressed: space radiation and microgravity.

Did you know? The longest human space flight in history lasted 437 days.

Exploring space is a very exciting challenge for humanity. Since the first human went into space in 1961, our success has been based on lots of hard work, research, preparation, and sacrifice. However, decades of research have revealed that we still have a lot to learn about living and working in space.

First, there's the problem of space radiation. Our universe is full of invisible radiation that mainly comes from stars (like the sun), including “dying” stars (like a supernova). Radiation is dangerous to humans because it is made up of extremely small, very high-energy particles that can cause a lot of damage to our bodies if they hit us. Here on Earth, we are safe from most space radiation because of the atmosphere and the magnetic fields that surround the planet. However, in deep space (far away from the Earth's atmosphere and magnetic fields), humans would be fully exposed to space radiation, which has the potential to be very harmful or even fatal. In order to safely travel through our solar system, astronauts would need ways of protecting themselves from these dangerous invisible particles. Possible solutions include better shielding for spacecraft and medicines that would help the cells in astronauts' bodies better resist radiation.

Did you know? Only 24 people have ever gone further into outer space than low Earth orbit, that is to say more than 2,000 km from the surface of the Earth.

That leaves the problem of microgravity. In space, there is very, very little gravity. But since it is not completely absent, we call it “microgravity.” Although floating in space looks like a lot of fun, it can actually cause health problems over time. Human beings need gravity to keep their muscles and bones strong. The more time astronauts spend in space, the more brittle their bones become and the more their muscles shrink. Deep space exploration would involve missions lasting months or years, so we need to find ways to keep muscles and bones as strong as possible. Otherwise, when the astronauts undertaking these missions finally land, they may break a leg just trying to stand up.

Although space radiation and microgravity are major obstacles to deep space exploration, there is a lot of great work being done around the world to help find the solutions that we require to safely travel further and further into the solar system. So, where do you want to go next?

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Kris Lehnhardt

Dr. Kris Lehnhardt is an Attending Physician and Assistant Professor at the George Washington University School of Medicine and Health Sciences who specializes in Emergency Medicine and Aerospace Medicine.  He is board certified in Emergency Medicine in both Canada and the United States and he works clinically in the Emergency Department at the George Washington University Hospital.

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