Thermochromic Programmable Metamaterial Particle Ensembles

The orbital deployment of a dust field is a method to remediate small debris (1 mm–1 cm). The debris passes through the field and experiences an induced drag force from collisions with the dust, lowering their orbital lifetimes. Programmable metamaterial particle ensembles (PMPEs), or programmable dust, expand the mission design space of active remediation techniques for small orbital debris. These particles harness environmental stimuli to passively self-regulate the decay rates of their orbits. The thermochromic PMPE, whose variation in optical properties with temperature leads to asymmetric solar radiation pressure (SRP) force over the orbit cycle, is analyzed here with an emphasis on the design, capability, and enabling materials. At sufficiently high altitude, the total force imparted by SRP can accelerate or reverse the decay of the particle’s semimajor axis through the cumulative effect of adding or subtracting energy from the system over many orbits. For idealized, composite thermochromic PMPEs, particle decay rates may be doubled, or the orbits can be raised, effectively canceling out the effects of atmospheric drag. A currently feasible design for a thermochromic PMPE is presented, resulting in modest increases in the lifetime of the particle’s orbit. The implications of the presented results extend to improvements in the current state-of-the-art methods for the remediation of small debris. Compared to inert particles, the use of PMPEs as “programmable dust” in debris remediation may enable novel concepts of operations and improve mission efficacy.