When you look at Venus and the Earth, they formed at about the same place in the solar system. They're made of about the same materials; they're about the same size.

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?'

Prior to Magellan, due to the fact that we knew it was so hot on Venus, we thought that the rocks at the surface would behave more plastically, more like Silly Putty than like solid rock in the way that we think of it, like the rocks that I'm sitting on.

Ellen Stofan Quotes