Image of navigation Doppler LiDAR
NASA’s navigation Doppler LiDAR instrument is comprised of a chassis containing electro-optic and electronic components, and an optical head with three telescopes. (Credit: NASA)

For planned robotic and crewed missions to the Moon and Mars, NASA is developing and testing precise landing and hazard-avoidance technologies. A combination of laser sensors, a camera, a high-speed computer, and algorithms will give spacecraft artificial eyes and analytical capability.

Terrain relative navigation identifies where the spacecraft is and sends that information to the guidance and control computer, which is responsible for executing the flight path to the surface. Midway through the descent, navigation Doppler LiDAR measures velocity and range, adding to the precise navigation information coming from terrain relative navigation.