Living in space is not just a fantasy anymore. It may actually be possible within our lifetimes — or at least Obama thinks so.In a CNN op-ed, the president thinks we'll be able to arrive on Mars by the 2030s and eventually settle there. That's a bit less ambitious than Elon Musk , who claims humans will arrive on Mars by 2025.The U.S. government and NASA are currently figuring out how to get people safely to the planet. Obama thinks the private companies he's working with will be able to send astronauts to the International Space Station within just two years.They're also working to "build new habitats that can sustain and transport astronauts on long-duration missions in deep space," he wrote. "These missions will teach us how humans can live far from Earth — something we'll need for the long journey to Mars."Could this be the cause Obama takes up once he's not busy being president? He does seem excited about it.The article ends with a poetic description of a scene he'd one day like to enjoy with his grandchildren."We'll still look to the stars in wonder, as humans have since the beginning of time," he imagines. "But instead of eagerly awaiting the return of our intrepid explorers, we'll know that because of the choices we make now, they've gone to space not just to visit, but to stay — and in doing so, to make our lives better here on Earth."