Humans can expect to face major challenges during an expedition to Mars. It is proven that humanity can travel in space for more than two years. In total, Sergei Constantinovich Krikalev, a Russian cosmonaut, spent more than eight hundred and three days in Earth orbit (Lyndon B. Johnson Space Center, 2005). The expedition to Mars would require the crew to travel six months to the planet, one year of living on the planet, and a six-month return trip to Earth. Russian cosmonaut Valery V. Polyakoz, with a total of four hundred and thirty-eight days for a single stay in Earth orbit, shows that humanity is capable of a twelve-month round trip to Mars (Schwirtz, 2009) . Earth's orbit has brought certain advantages to space exploration, such as the magnetic field of cosmic radiation and proximity to Earth in case of emergency (Jones, 2009). The further humans move from Earth, the greater the risks. The main risks to human health during flight to Mars, life on Mars and return to Earth are: radiation exposure, biological problems induced by weightlessness, spacecraft malfunctions and problems psychological problems caused by isolation. humans to Mars, is the amount of radiation they would be exposed to while traveling through space. Most space agencies set amounts of radiation that astronauts can be exposed to throughout their lives; the general limit is one sievert (Gelling, 2013). One way to minimize the threat of radiation exposure is to have appropriate shielding for those passing through the interior of the spacecraft. A lesson from the Curiosity mission to Mars is that having adequate shielding would allow a twelve-month journey to and from Mars, exposing only the astronaut...... middle of paper ......usion, the challenges major challenges that humans could face in an expedition to Mars and back; are radiation exposure, biological problems induced by weightlessness, spacecraft malfunctions, and psychological problems caused by isolation. The solution to radiation exposure is to provide adequate protection for astronauts. The physiological problems humans experience in a weightless environment could be entirely eliminated if they had artificial gravity. If a malfunction were to occur on the spacecraft or at the temporary facility on Mars, it would be prudent for the astronauts to have a backup vessel. Additionally, providing some form of normalcy for astronauts in space and on Mars, such as artificial gravity, books to read, movies to watch, games to play, and the creation of a weekly support group, would promote a healthy psychological state of mind..