Data-Driven Multi-Satellite Orbit Selection for Nighttime Wildfire Remote Sensing

Dangerous wildfire has increased in frequency throughout the last several years. Novel distributed spacecraft missions (DSMs), which occupy low Earth orbit (LEO) and constitute multiple satellites, can provide high spatial and temporal resolution necessary for monitoring and surveillance of active fire. Nighttime observation can support lower signal-to-noise ratios in measurement acquisition due to the significant contrast between the fire brightness and dark background when the solar elevation angle is ≤ 0°, leading to enhanced detection of cooler fires at early stages of ignition.We conduct a parameterized study, determining the optimal configuration of 1-3 satellites to observe wildfire at night in LEO, for various altitudes, sensor swath sizes, and solar elevation thresholds, which define “night”. We determine the best satellite inclinations that can simultaneously maximize the total observed wildfire area given cloud obscuration, obtain regular measurement intervals, and minimize degraded science products from terminator periods throughout the mission lifetime.Wildfire prevalence is modeled from historical burn area datasets, filtered for high-burn events, while total cloud cover is derived only from historical datasets. In total, we simulate ~500,000 architectures, over a 2-year mission lifetime. Given a single satellite, a sun-synchronous orbit (SSO) at 12:00/24:00 equatorial crossing time provides superior nighttime measurement potential relative to any inclined orbit (INC). When two satellites are considered, and nighttime measurements are required, the SSO remains superior. However, if dawn/dusk measurement is valid, one INC supporting one SSO meets objectives. For three-satellite architectures, two INC with one SSO for relaxed nighttime constraints is optimal, whereas all 3 should be SSO with a dark night observation requirement. Overall, a general placement of satellites is optimal, rather than constrained to traditional constellation structures, such as Walker-Delta.