GIANT stands for Goddard Image Analysis and Navigation Tool, and it is basically an optical navigation software. That's right, it uses images snapped by cameras, lidar, and other sensors to find the best way forward, kind of like we humans do when we use our eyes to see where we're going.

Simply put, GIANT only needs a picture of the target to be able to determine distance, the mass and center of a spinning object, and even identify landmarks on the surface of a celestial body. Three-dimensional maps of potential landing zones can also be generated, complete with potential hazards.