Falcon Neuro: an event-based sensor on the International Space Station

Abstract

We report on the Falcon neuro event-based sensor (EBS) instrument that is designed to acquire data from lightning and sprite phenomena and is currently operating on the International Space Station. The instrument consists of two independent, identical EBS cameras pointing in two fixed directions, toward the nominal forward direction of flight and toward the nominal Nadir direction. The payload employs stock DAVIS 240C focal plane arrays along with custom-built control and readout electronics to remotely interface with the cameras. To predict the sensor's ability to effectively record sprites and lightning, we explore temporal response characteristics of the DAVIS 240C and use lab measurements along with reported limitations to model the expected response to a characteristic sprite illumination time-series. These simulations indicate that with appropriate camera settings the instrument will be capable of capturing these transient luminous events when they occur. Finally, we include initial results from the instrument, representing the first reported EBS recordings successfully collected aboard a space-based platform and demonstrating proof of concept that a neuromorphic camera is capable of operating in the space environment.

Sprite Durations Measured With a Neuromorphic Sensor

“…First, they are inherently‐fast sensors, and thus are a low‐cost alternative to high‐speed cameras for probing fast, transient processes within lightning and sprites. Second, they output data at a low rate, making them ideal for long duration observations, such as done from the ground by the remotely‐operated LEONA network in South America (São Sabbas et al., 2017), or in space‐based missions, such as the Falcon‐NEURO, Falcon‐ODIN, and THOR‐DAVIS onboard the ISS (Balthazor et al., 2023; Chanrion et al., 2023; McHarg et al., 2022).…”

“…The inherently‐fast nature of neuromorphic sensors combined with their low data rate make them ideal for the observation of fast transient sources such as sprites and lightning, particularly for remotely‐operated, long‐duration observations. These characteristics of neuromorphic sensors have inspired the development of three missions to observe lightning and sprites from the International Space Station (ISS) (Balthazor et al., 2023; Chanrion et al., 2023; McHarg et al., 2022). In this work, we report the first ground‐based observations of sprites with a neuromorphic sensor, and compare them to conventional frame‐based cameras.…”

Modeling and decoding event-based sensor lightning response

“…Adapted from. 19 where θ e-folds is the threshold in log-signal units and θ percent is the reported threshold value, representing a fractional change in input signal. For small values, θ e-folds ≈ θ percent .…”

“…Counter-intuitively, with selected parameters (θON = 0.3 and refractory period = 140 µs), the slower bandwidth setting results in more expected events (six) than the faster setting (four). Adapted from 19.…”