Rachel Oliver, Air Force Institute of Technology; Paul Rickershauser, Air Force Institute of Technology; Matthew McHarg, United States Air Force Academy
https://doi.org/10.64861/VTPN8548
Keywords: Event-Based Sensors, Neuromorphic Sensors, Space-Based, Space Domain Awareness, Concepts of Operations
Abstract:
Event-based vision sensors (EVS) are an emerging technology for Space Domain Awareness (SDA), offering high dynamic range and temporal sensitivity while reducing data production and power consumption. These benefits derive from their independently and asynchronously operating pixels that record binary events only when a logarithmic threshold positive or negative change in photocurrent is reached. The possibility of power and data reduction is particularly attractive to match the constraints for power, processing, and communication bandwidth of space-based sensing applications. Therefore, these sensors can be a key enabler for space-based SDA, improving detection and tracking of space assets in an increasingly complex environment. To explore this potential, we modify a low-light EVS simulation to create the Neuromorphic Event-Based Unified Luminance Asset-simulator (NEBULA). Through NEBULA, we evaluate the capabilities and constraints of commercial off-the-shelf (COTS) EVS for satellite-based SDA. First, we compare the synthetic events against on-orbit data. Then we examine resident space object (RSO) and star observability, particularly as a function of slew-rate and background zodiacal light to consider the potential design implications of space-based EVS.
To simulate a space-based system, NEBULA adds the observer’s orbital motion and attitude to determine pointing at each simulation time step allowing for the dynamic motion a satellite may exhibit. Additionally, without atmospheric aberrations, it incorporates the now dominant optical system aberrations driving non-diffraction limited dispersion of energy on the sensor. Next, we include modifications to the lighting within the scene to increase accuracy in the generated event stream. These modifications include a zodiacal light model to capture a more realistic background photon-flux due to light scattering off local solar system dust, visibility considerations given the geometry of reflections and shadows between the earth, sun, observing satellite, and observed satellites, and a reflectance model that allows for high phase angle reflections.
To test NEBULA’s capabilities, we compare the model with data from Falcon ODIN, a United Space Air Force Academy EVS payload aboard the ISS. The comparison with a real dataset provides a basis to examine the challenges associated with simulating the complex space environment. These in-turn drive new additions to the simulator we will consider in the future to improve fidelity of the synthetic event stream.
Working with the current fidelity of NEBULA, we explore the relationship of event generation and slew rate of space-based platforms. EVS systems may rely on induced motion to generate desired events of an observation since consistent photon flux on a pixel will not yield events. Therefore, understanding the impact of slew rate is imperative. We leverage the simulator to generate events while slewing with different rates through fields of known magnitude stars and background zodiacal light to modify the background noise floor. Through this evaluation, we compare the overall event-rate and limiting visual magnitude as a function of slew-rate. The suppression of up to 36.7% of the background event-rate highlights the importance of including zodiacal light in future space-based simulations.
In summary, this work documents a significant step forward with the synthetic event-generation capabilities for space-based EVS systems. With limited examples of space-based EVS, the development of NEBULA is critical to assess viability of strategies leveraging these sensors in space to conduct SDA. The work incorporates necessary additions into an existing EVS simulation to handle a moving observational platform that considers both satellite orbit and attitude, optical system aberrations, and alternative light sources such as zodiacal light. Through comparison of the modified tool with Falcon ODIN data, we emphasize the importance of those additions and highlight items for future simulation development.
Date of Conference: September 15-18, 2026
Track: Space-Based Assets