Spatial and temporal analysis of the Polar Radiant Energy in the Far-InfraRed Experiment (PREFIRE) intersections

Abstract

The Polar Radiant Energy in the Far-InfraRed Experiment (PREFIRE) will use two 6U CubeSats to continuously measure spectral far-infrared (FIR) emissions for the first time in the modern satellite era. By strategically operating two CubeSats in separate sun-synchronous orbits, PREFIRE will achieve frequent orbit resampling, or intersections, that afford insights into the underlying polar processes that modulate FIR emissions. These orbit intersections are integral to PREFIRE science and will likely feature prominently in future CubeSat missions, motivating methods to characterize resampling distributions. Accordingly, this thesis develops new methods to locate orbit intersections and extract co-located pixels between crossovers. Such methods are then applied to simulated PREFIRE orbits to characterize the spatial and temporal distribution of hypothetical PREFIRE intersections and identify a subset with minimal revisit times that can be used for inter-calibration during the mission. This analysis confirms that hundreds of PREFIRE intersections are anticipated each day, with the majority (>75%) occurring poleward of 66.5° latitude. Notably, the addition of a second CubeSat nearly quadruples the number of sub-daily polar intersections. Spatial and temporal resampling coverage is clearly enhanced when more than one CubeSat is enlisted, securing greater latitudinal representation and more diverse time differences between crossovers compared to a scenario in which only a single CubeSat is deployed. Additionally, when two CubeSats are placed at different altitudes, we find that their intersections exhibit time-varying, cyclic coverage. This orbit configuration further yields simulated intersections between latitudes 72° and 78° with time differences sufficiently short for inter-calibration. Finally, we consider three conceptual cases that indicate PREFIRE intersections will be valuable for capturing processes like sea ice melt and high-latitude cloud cover change as well as for inter-calibrating the PREFIRE sensors.