Stofan wants to land a man on Mars by the mid-2030s . NASA chief scientist , Ellen Johnson , wants humans on Mars by 2020 . Astronauts will take 8 years to reach Mars , face radiation , thin air . Studying Mars could help us better understand Earth . Believes there must be intelligent life in our universe .
NASA chief scientist , Ellen Johnson , wants humans on Mars by 2020 . Astronauts will take 8 years to reach Mars , face radiation , thin air . Studying Mars could help us better understand Earth . Believes there must be intelligent life in our universe .