China and the US are in a race to Mars - with both nations due to land a rover on the Red Planet this month, and plans for future missions already in development. This new 'space race', unlike the battle to the Moon between the US and Soviet Union, is likely to be a much more crowded field, including private firms and smaller nations - such as the United Arab Emirates who have a probe en-route to Mars now. SpaceX founder Elon Musk reiterated in a recent interview that his aim is to land the first humans on Mars by 2026 - that is seven years earlier than NASA's earliest goal.