LIDAR, or Light Detection and Ranging, has been a powerful tool in Earth observation since at least the 1990s, when satellites began using this active sensing technology to augment the passive measures - such as visual light photography - that characterise most systems.
NASA outlines LIDAR's advantages as being useful at night, and in a laser's tight beam - which does not disperse as it travels from its source, as ordinary light does, enabling measurement of a narrow column of the atmosphere with each light pulse.
A space-based LIDAR can also see through thin or broken clouds. NASA and the US Geological Survey have taken advantage of this penetrating capability to survey underwater regions from an airborne LIDAR.
And, LIDAR is also likely to play a significant part in future attempts to land on other worlds. Boeing, for example, has researched a LIDAR-based system for giving a spacecraft autonomous capability to select a safe landing site on the Moon.