Orbiting more than 370 kilometres above Earth in the International Space Station is a tough, alien environment for a human body. There's no gravity to pull fluids out of the brain as there is at home, radiation exposure is far above what we already know can cause cancer and although astronauts work out a couple of hours a day, bones and muscles still quickly lose mass. After more than 50 years of human space travel, those are the health problems we do know. And those trips have mostly been six months at the most. The next giant leap in space aims to get humans much farther into deep space: Mars. Just getting to the red planet would take six months. A full expedition would likely take two to three years. The United States has announced it wants humans to fly by and eventually land on Mars in the 2030s. Considering we don't really know the health effects of travelling in space for more than six months, is it realistic? Dan Riskin invesigates the technology required for humankind to reach Mars and if our bodies would even be able to survive the trip.