Researchers have demonstrated GPS-free landing technology designed to guide spacecraft safely to the surface of asteroids.
Last week Astrobotic successfully flew the sensor package made up of two cameras, an inertial measurement unit, and a scanning laser on an unmanned helicopter operated by a pilot on the ground in preparation for demonstration of this capability on a propulsive lander.
The helicopter flight is one of a series of flights to occur over the next few months to verify performance of the underlying hardware and software, and when the software has reached stability with predictable performance it will be tasked to land the helicopter by itself without GPS.
"The pair of cameras work together like human eyes to measure distance and track motion. The scanning laser gives precise distance measurements and enables us to pick out hazards as small as a curb. The sensor combines these sensors with an inertial measurement unit—the device that enables smartphones to switch from landscape to portrait mode-- to build its models," explains Kevin Peterson, Director of Guidance, Navigation, and Control for Astrobotic.
Astrobotic has been selected by NASA for flight opportunities on a propulsive lander which will culminate in a fully autonomous landing demonstration with hazard detection, trajectory planning, and closed-loop control.
The sensor package relies on terrain relative navigation, which enables precise landing on planetary bodies without GPS.
The spacecraft will autonomously compare imagery captured from cameras with maps from satellite imagery to determine its location and the firm hopes the technology will revolutionize access to planetary surfaces through a 100-fold increase in the accuracy of planetary landings.
"This flight opportunity represents a major milestone not just for us, but for spacecraft in general. We’ll be the first to demonstrate a GPS-denied propulsive landing from high altitude that can re-plan its route after discovering its targeted landing area is unsafe to land," says Peterson.