Jim Shell, Novarum Tech, LLC
Keywords: Optical imaging, on-orbit servicing, active debris removal
Abstract:
The prospects of on-orbit satellite servicing and active debris removal (ADR) missions have been accelerating. Long-term orbital debris growth projections, coupled with decreasing launch costs and proposed mega constellations of small satellites has prompted the exploration and maturation of satellite designs which enable on-orbit servicing and orbital debris removal. The majority of these satellite design concepts employ an optical imaging payload. Imaging payloads and their associated machine vision processing may be used to accurately determine object dynamics which are necessary to assess suitable candidate objects for ADR and understand probable ingress conditions.
Spatial resolution is often the key imaging payload performance parameter to establish the minimum range at which features of interest may be determined given an optical aperture size. Ideal imaging conditions are obtained by matching the orbital planes of candidate objects, thus minimizing the relative angular motion. Upon matching the orbital plane, minimal fuel may be expended to achieve the minimum range required to assess the suitability of ADR candidates. However, the initial orbital plane alignment is expensive due to the high relative velocity change required and the depletion of propellant, often the limiting factor for such missions. The ability to image objects orbiting out-of-plane dramatically improves the overall mission effectiveness by expanding the number of candidate survey objects.
This work explores the design trade space to discover the optimal spatial imaging resolution performance from a small satellite while maximizing the number of targeted objects and minimizing fuel expenditures. This work also demonstrates that spatial imaging resolution is a function of the aperture size, range, angular slew rate of the imaging satellite, and relative angular rate of the targeted object. In particular, improved satellite attitude control technologies enable higher performance imaging from smaller aperture sizes. Smaller aperture sizes, in turn, translate to overall lower satellite and mission costs. Quantifying the relationships among these variables enables optimization of imaging performance at the satellite system level for any given requirement set for ADR missions as well as on-orbit servicing missions.
Date of Conference: September 11-14, 2018
Track: Space-Based Assets