This simulated 3-D perspective view of Chasma Boreale, a canyon that reaches 570 kilometers (350 miles) into the north polar cap on Mars, was created from image data taken by NASA's Mars Odyssey spacecraft.
NASA/JPL/Arizona State University, R. Luk
Alex Longo makes a pitch at the Lunar and Planetary Institute in Houston, Texas, in October 2015. The Institute sponsored the conference to pick a landing site for the first human landing on Mars. Long has proposed a site for a different mission — a rover landing.