As we visit Mars multiple times, we will build up infrastructure on the surface to expand the capabilities and reach of humans on Mars.

My key aim is to get man on the surface of Mars by the mid-2030s.

We want to make sure we get living astronauts to the surface of Mars.

We like to talk about pioneering Mars rather than just exploring Mars, because once we get to Mars, we will set up some sort of permanent presence.

We have to ask, 'How can we break a huge challenge like sending humans to Mars into a series of doable, affordable steps? How can we break that problem down into chunks in order to keep making progress?'

Mars missions will require up to three years in reduced gravity, so we need to make sure astronauts can not only survive but thrive as they move outward to explore this new world.