Geo-engineering using dust grains in heliotropic elliptical orbits

This paper examines the concept of a Saturn-like Earth ring comprised of dust grains to offset global warming. A new family of non-Keplerian periodic orbits, under the effects of solar radiation pressure and the Earth’s oblateness J2 perturbation, is selected to increase the lifetime of the passive cloud of particles and, thus, increase the efficiency of this geo-engineering strategy. An analytical model is used to predict the evolution of the dust due to solar-radiation pressure and the J2 effect. The attenuation of the solar radiation can then be calculated from the ring model. In comparison to circular orbits, eccentric orbits yield a more stable environment for small grain sizes and therefore achieve higher efficiencies when the orbital decay of the material is considered. Moreover, the special orbital dynamics experienced by high area-to-mass ratio objects, influenced by solar radiation pressure and the J2 effect, ensure the ring will maintain a permanent heliotropic shape, with dust spending the largest portion of time on the Sun facing side. It is envisaged that small dust grains can be released with an initial Δv to enter an eccentric orbit with Sun-facing apogee. Finally, an estimate of 5.94x1011 kg is computed as the total mass required to offset the effects of global warming.