Popular Science By Sarah Fecht posted Apr 24th, 2017
Today, during a phone call with astronaut Peggy Whitson on the International Space Station, President Trump joked that he hoped NASA would land astronauts on Mars by the end of his first term in 2020.
Obviously, this timeline is completely unreasonable for an agency that's already running behind on its plan to get to Mars by the 2030s. Getting to Mars is going to be incredibly difficult, with a lot of moving pieces that all need to fit together seamlessly.
Here's a to-do list of just some of the things NASA would need to get done by 2020:
More:
http://www.popsci.com/trump-mars-2020