An artist's concept shows a NASA Mars exploration rover on the surface of Mars. The twin rovers Spirit and Opportunity were launched in 2003 and arrived at sites on Mars in January 2004.
NASA engineers on the flight team celebrate the InSight spacecraft's successful landing on Mars at the NASA Jet Propulsion Laboratory in Pasadena, Calif., on Monday.
Al Seib/AFP/Getty Images
A dust storm has reduced sunlight and visibility on Mars. But NASA's Curiosity rover, seen in a self-portrait taken last week in the Gale Crater, runs on nuclear energy and is powering through.
NASA/JPL-Caltech via AP
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.