Cam Key, Slingshot Aerospace; Alex Ferris, Slingshot Aerospace; Max Geissbuhler, Slingshot Aerospace; Joshua Horwood, Slingshot Aerospace; Keegan Kochis, Slingshot Aerospace; Jeff Shaddix, Slingshot Aerospace; Jeff Aristoff, Slingshot Aerospace
Keywords: Low Earth Orbit, Telescopes, Dim Target Detection, Wide Field-of-View, Optical Systems, Daytime Satellite Tracking, Mega-Constellations, Space Traffic Management
Abstract:
The low Earth orbit (LEO) satellite population is burgeoning. Due to ongoing efforts by commercial, academic, and government programs, over 60,000 new LEO satellites are expected to be launched over the coming decade. As the LEO population grows, so does the frequency of conjunctions, on-orbit anomalies, debris shedding, and other situations that pose risk to manned and unmanned spaceflight. The unprecedented rate of growth of the LEO population due to planned mega-constellations necessitates timely collection of LEO space domain awareness (SDA) data for improved custody, collision avoidance, and feature aided anomaly detection at scale.
Existing sensor systems are either costly or not scalable enough for mega-constellation tracking. Radars, traditionally the sensor of choice for LEO tracking, can be highly performant, can operate day and night, and are nearly immune to weather. However, such systems come at a high cost, which limits the ease with which they can be deployed to many sites for improved geographic coverage. Daytime-capable telescopes, on the other hand, are comparably low-cost and therefore easy to proliferate, but can typically only collect on, at most, a few thousand unique LEO RSOs per 24-hour period. This makes daytime-capable telescopes ideal for achieving high revisit rates and superb custody on small populations (hundreds) of high-interest objects in LEO, but poorly suited for tracking mega-constellations.
LEO-optimized optical fences provide an attractive solution, but one that has historically suffered from technological hurdles to become reality. Leveraging ultra-wide field of view (UWFoV) electro-optical sensors, an optical fence can image large portions of the sky to track most targets passing overhead simultaneously. This feature makes such systems well-suited to applications like uncued tracking, new foreign launch tracking, and, relevant to the present work, tracking extremely high RSO populations in LEO. The traditional downsides of UWFoV LEO optical fences have been their poor detectability (relative to a narrow field of view telescope), weather limitations, and the upper bound on revisit rates achievable with such systems due to LEO occlusion by the Earth during much of the night. With advanced image processing algorithms developed by Slingshot, we show that all-sky LEO-optimized optical fences can achieve detectability substantially higher than the prior state of the art, making such systems well-tailored to tracking objects down to cubesat scale. We also show that, by deploying such systems to several, strategically chosen locations superb tracking of mega-constellations can be achieved despite weather outages and system viewing limitations.
In summary, we investigate how a hypothetical network of UWFoV LEO-optimized optical fences can provide enhanced space domain awareness for current and planned mega-constellations. We perform sensor access and data quality simulations accounting for weather, solar exclusion, and accuracy limitations to present salient performance statistics such as state quality and time since last observation. All simulations use real weather data, mega-constellation orbital parameters based on real objects, and sensor characteristics derived from real-world operational and field test data.
Date of Conference: September 27-20, 2022
Track: Optical Systems & Instrumentation