Publications

Lunar polar regions and permanently shadowed regions (PSRs) are a key component of NASA's exploration objectives for the lunar surface, given their potential for a high abundance of volatiles like water. The Massachusetts Institute of Technology (MIT) Big Idea Challenge Team proposed the use of deployable towers to support robotic and remote exploration of these PSRs, alleviating limitations imposed by the rugged terrain. This deployable tower technology (called MELLTT) could enable an extended ecosystem on the lunar surface. This paper seeks to build on this initial concept by showcasing the advantages of self-deploying lightweight lunar towers through the development of various payload concepts. The payloads include 5-kg packages for an initial proof-of-concept deployment, as well as 50-kg payloads and payloads across multiple towers for future exploration architectures. The primary goal of a 5-kg tower payload is to return unique scientific data from a PSR while minimizing risk to a tower technology demonstration mission. Concepts include passive imagers to provide a step-change improvement in resolution, solar reflectors capable of illuminating PSRs, communications infrastructure for human and robotic exploration, a power beaming demonstration, and a PSR impactor. These payloads demonstrate the utility of towers on the lunar surface and how incremental improvements in the capability of towers can further NASA's exploration program.

In response to a series of midair collisions involving commercial airliners, Lincoln Laboratory was directed by the Federal Aviation Administration in the 1970s to participate in the development of an onboard collision avoidance system. In its current manifestation, the Traffic Alert and Collision Avoidance System is mandated worldwide on all large aircraft and has significantly improved the safety of air travel, but major changes to the airspace planned over the coming years will require substantial modification to the system. Recently, Lincoln Laboratory has been pioneering the development of a new approach to collision avoidance systems that completely rethinks how such systems are engineered, allowing the system to provide a higher degree of safety without interfering with normal, safe operations.

Many aviation safety studies involve estimating near mid-air collision (NMAC) rate. In the past, it has been assumed that the probability that an NMAC leads to a mid-air collision is 0.1, but there has not yet been a comprehensive study to serve as a basis for this estimate. This paper explains how to use existing encounter models, a flight simulation framework, three-dimensional aircraft wireframe models, and surveillance data to estimate mid-air collision risk. The results show that 0.1 is an overly conservative estimate and that the true rate is likely to be an order of magnitude lower.