Description: The proposal describes a next generation 3D imaging lidar (IML) suitable for a uniquely wide range of space applications - from orbital mapping and proximity operations of small bodies such as asteroid and comets, to full scale entry, decent and landing operations on other planetary bodies. Low Earth Orbit operations such as rendezvous and docking between spacecraft, and space debris search and collection can also be accommodated. Such versatility is made possible system by a system architecture which merges the architectures of two high performance imaging lidars - the Sigma Space 3D Imaging Lidar and the Imaging Lidar for planetary landing developed by the European Space Agency. The result is a highly modular architecture that is scalable and "open" in terms of future development of the underlying technologies thus providing a path for reusable NASA investment. The design combines several advanced technologies which have matured independently of each other into a state-of-the-art system with performance parameters and flexibility greatly exceeding those of the existing instruments. Its key advantage is the operation at the ultimate single photon sensitivity level which minimizes instrument Size, Weight, and Power (SWAP). It is combined with other useful features such as high spatial and range resolution, wide FOV, highly flexible scanning with variable field of regard (FOR), autonomous target acquisition and tracking, and programmable surface measurement rates up to several 3D Megapixels per second (Mpix/s) during orbital mapping and spacecraft entry, descent and landing operations. It advances the state of the art by extending the range of 3D measurements from 10m to 10km, improving the measurement accuracy and the spatial resolution and significantly reducing the impact of incorporating such sensors on the spacecraft in terms of SWAP, spacecraft accommodation complexity, and cost.

Benefits: The technology developed here can be used to map the surface during descent and landing operations on a wide variety of extraterrestrial bodies, including asteroids, comets, planetary moons, and even planets. Comparable high resolution mapping from higher orbits about large planets or moons, however, would require appropriate increases in laser power and/or receive aperture to sustain the ranging link at the desired resolution. For these larger bodies, the scanner can be placed behind the telescope in order to significantly reduce scanner size and weight. Tradeoff studies between current Sigma and ESA approaches to detectors and range receivers conducted under this SBIR are expected to improve on the performance and characteristics Sigma's current suite of single photon sensitive, airborne 3D imaging lidars. NASA's demonstrated interests, and those of affiliated universities, have included ice sheet mapping in Greenland and Antarctica and biomass measurement in support of global warming research.

Sigma already has a broad base of non-NASA customers interested in its current 3D imaging lidars including all three major branches of the DoD (Army, Navy, and USAF), USGS, universities and commercial aerial surveying and mapping companies. Beyond general topographic mapping and military surveillance applications, other non-NASA customer interests include forestry management, undersea mapping of coastal regions and river beds, searches for mines and submarines, etc. Because of their extreme sensitivity and ability to form high resolution images of a target, photon-counting 3D imaging lidars have potential application to the safe landing of manned, or even unmanned drone, helicopters during "brownout" or low ground visibility conditions. This has been an important goal of the US military, aimed at reducing the number of helicopter crashes that occur in sandy locales such as Iraq where the upwelling sand prevents the pilot from seeing the targeted landing site. In the civilian sector, pilots of helicopters in the medical, police, traffic, and transportation sector encounter similar issues during periods of heavy ground fog.