Met him once after he gave a talk on campus. Decent dude.
He asked the lecture hall an interesting question about the explorer mindset. It was during the era of the MarsOne media-fueled vapour hype. "Would you take a one-way trip to Mars?" And then started asking why, or why not (the consensus of the room was nearly unanimously "no"). And talked about explorers ancient and modern, and how risk was no longer tolerated. Very interesting fellow.
RIP.