Our team recently finished integrating Navigation Doppler LiDAR (NDL) with Griffin-1, our lunar lander built for the South Pole. NDL is a key piece of how Griffin-1 will perceive how it is moving during descent and help us land in some of the Moon’s trickiest terrain.
Why NDL Matters
Landing at the lunar south pole is challenging. Shadows stretch for miles, terrain is uneven, and there is no room for error. Griffin-1 already relies on terrain relative navigation and hazard detection to pick out a safe place to touch down, but NDL sharpens that picture. It gives the lander a clear read on how fast it is moving and how high it is, updating continuously as the spacecraft descends so the guidance system can respond in the moment.
The sensor itself was developed at NASA’s Langley Research Center in Hampton, Virginia and nurtured by NASA’s Space Technology Mission Directorate (STMD). It uses laser pulses and the Doppler effect to track motion relative to the surface. This LiDAR system is small, lightweight, and efficient: perfect for Griffin, where every gram and watt counts.
NDL integrates with our other safe and precise landing sensors, including terrain relative navigation and hazard detection. During descent, NDL continuously tells the flight computer how fast the lander is moving relative to the surface and in what direction. That information lets the spacecraft adjust engine firings and attitude on the fly, helping Griffin-1 reach its target landing zone with confidence.
Test Like You Fly
Every integration step is tested under realistic conditions, including software-in-the-loop, testing with our mobile FlatSat, helicopter and Xodiac rocket testing, and full system simulations. We want to be sure that when Griffin-1 begins its descent, all the systems are reading, responding, and coordinating exactly as expected. NASA’s investment in the technology and its transition to a commercial product enables us to put them to work on operational missions. For Griffin-1, that capability is what will enable us deliver payloads to the lunar surface with confidence on our upcoming flight.