Stu Spath, InSight program manager, Lockheed Martin Space, discusses NASA's InSight mission during a prelaunch media briefing, Thursday, May 3, 2018, at Vandenberg Air Force Base in California. 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. Photo Credit: (NASA/Bill Ingalls)

Stu Spath, InSight program manager, Lockheed Martin Space, discusses NASA's InSight mission during a prelaunch media briefing, Thursday, May 3, 2018, at Vandenberg Air Force Base in California. 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. Photo Credit: (NASA/Bill Ingalls)

Stu Spath, InSight program manager, Lockheed Martin Space, discusses NASA's InSight mission during a prelaunch media briefing, Thursday, May 3, 2018, at Vandenberg Air Force Base in California. 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. Photo Credit: (NASA/Bill Ingalls)

Stu Spath, InSight program manager, Lockheed Martin Space, left, and Tom Hoffman, InSight project manager, NASA JPL, discuss NASA's InSight mission during a prelaunch media briefing, Thursday, May 3, 2018, at Vandenberg Air Force Base in California. 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. Photo Credit: (NASA/Bill Ingalls)

During a prelaunch briefing at Vandenberg Air Force Base in California, Stu Spath, InSight Program Manager with Lockheed Martin Space, speaks to members of the media. The presentation focused on NASA's Interior Exploration using Seismic Investigations, Geodesy and Heat Transport, or InSight, Mars lander. InSight is scheduled for liftoff May 5, 2018, atop a United Launch Alliance (ULA) Atlas V rocket from Space Launch Complex 3 at Vandenberg. The spacecraft will be the first mission to look deep beneath the Martian surface studying the planet's interior by measuring its heat output and listen for marsquakes.

CAPE CANAVERAL, Fla. – Stu Spath, chief spacecraft engineer with Lockheed Martin, speaks to a group of Tweetup participants at the Kennedy Space Center Visitor Complex in Florida during prelaunch activities for the agency’s Gravity Recovery and Interior Laboratory (GRAIL) mission. Participants toured NASA’s Kennedy Space Center and got a close-up view of Space Launch Complex 17B at Cape Canaveral Air Force Station. The tweeters will share their experiences with followers through the social networking site Twitter. GRAIL will fly twin spacecraft in tandem around the moon to precisely measure and map variations in the moon’s gravitational field. The mission will provide the most accurate global gravity field to date for any planet, including Earth. This detailed information will reveal differences in the density of the moon’s crust and mantle and will help answer fundamental questions about the moon’s internal structure, thermal evolution, and history of collisions with asteroids. The aim is to map the moon’s gravity field so completely that future lunar vehicles can safely navigate anywhere on the moon’s surface. Launch is scheduled for 8:37:06 a.m. EDT Sept. 8. For more information, visit http://www.nasa.gov/grail. Photo credit: NASA/Gianni Woods