Connor Gray, AstroSweep; Benjamin Hall, LATscan; Alexander Pace, AstroSweep
https://doi.org/10.64861/MAER9178
Keywords: orbital debris, space debris, momentum coupling, laser ablation, low Earth orbit, debris remediation, laser-material interaction
Abstract:
Millimeter-to-decimeter orbital debris is a high-consequence SSA/SDA problem because the population is large, typical relative velocities in LEO are hypervelocity, and many objects are below ground-based tracking thresholds. This paper examines in-situ mitigation of small debris using a space-based laser and derives quantitative feasibility bounds that connect laser parameters to achievable risk reduction under realistic engagement-time constraints._x000D_
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For millimeter-class debris, the objective is complete hazard removal. We use first-principles energy accounting to estimate the energy required to heat representative metallic debris from an initial temperature through melting and vaporization, and to account for additional losses associated with incomplete absorption and ejecta plume formation. We define debris as removed if its mass is reduced below a threshold of 9e-8 kg. This equates to approximately 11 Joules of Kinetic Energy at worst-case LEO collision velocities; similar to the muzzle energy of a BB gun. _x000D_
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For larger debris (centimeter to decimeter class), the objective is controlled impulse transfer via laser ablation to alter the debris orbit toward lower-consequence trajectories. In this regime, a focused spot produces a transient vapor/plasma layer; and recoil from ejecta imparts an impulse to the remaining body. We parameterize impulse in terms of ejected mass, effective ejecta velocity, pulse duration, and a momentum-coupling coefficient that captures material response and beam format. The resulting delta-v per pulse and cumulative delta-v are mapped to representative changes in orbital elements, with emphasis on perigee reduction when the impulse vector has a favorable component opposite the debris velocity._x000D_
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Because laser engagements are time-limited by relative motion, ablation requirements are coupled to a geometry-based dwell-time model. For a stand-off engagement radius, dwell time is derived as a function of relative speed and approach angle through an engagement volume. We explicitly analyze a constrained field of regard and compare it to full-sky coverage to quantify the reduction in available pulse budget. This directly bounds the total deliverable energy and impulse per encounter and therefore the maximum target size that can be eliminated or significantly perturbed in a single pass._x000D_
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The paper identifies key sensitivities that dominate feasibility: optical intensity at the target (spot size, beam quality, pointing stability), incidence angle and reflectivity-driven coupling, and target attitude and tumbling, which affect both effective dwell time on a given surface patch and the alignment of recoil with the desired impulse vector._x000D_
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Expected outcomes are engineering-level envelopes that relate laser power, pulse duration, repetition rate, and spot size to (1) single-pass elimination probability for millimeter-class debris and (2) achievable orbit change (delta-v, perigee reduction, and orbital lifetime bounds) for centimeter-to-decimeter debris as a function of geometry and number of encounters._x000D_
Date of Conference: September 15-18, 2026
Track: Space Debris