In this video Matt O’Dowd from PBS Space Time talks about the upcoming human missions to Mars. He presents many difficulties, that we have to overcome in order to colonize Mars. These range from creating self-sustaining life support system, interplanetary transportation and economical affordability. Questions: 1. When do you think we will send first humans to Mars? 2. Who will send humans to Mars, corporates or countries? 3. What is the greatest obstacle we have to overcome in order to colonize Mars?