NASA science chief to leave post by end of year

Thomas Zurbuchen, Associate Administrator of NASA's Science Mission Directorate, NASA Headquarters talks about Mars InSight during a pre-landing briefing, Sunday, Nov. 25, 2018 at NASA's Jet Propulsion Laboratory in Pasadena, InSight, short for Interior Exploration using Seismic Investigations, Geodesy and Heat Transport, is a Mars lander designed to study the "inner space" of Mars: its crust, mantle, and core. InSight is scheduled to touch down on the Red Planet on Monday, Nov. 26. (Bill Ingalls/NASA via AP)