Dimming the Sun (DimSun) Using Controllable Dust Cloud to Reduce Solar Insolation

Saptarshi Bandyopadhyay
NASA Jet Propulsion Laboratory

DimSun mission concept focuses on geoengineering using space-based solar radiation management. DimSun will reduce solar insolation by 1.16% using a controlled dust cloud, made with 0.3 micro-meter radius 90%-hollow spherical particles, at the Sun-Earth Lagrangian L1 point.

DimSun is inspired by a previous study that aimed to create an uncontrolled dust cloud of small regolith particles at the Sun-Earth Lagrangian L1 point, which required replenishment every 100 days. Our main NIAC-worthy innovation is to prevent orbital decay of this dust cloud using repulsive forces from multiple spacecraft, and eliminate the need for replenishment. DimSun can be reversed by deactivating the control spacecraft, causing the dust cloud to disperse within 100 days. At a rough cost estimate of $134 Billion one-time fixed cost (which includes 43% margin) and some additional recurring maintenance cost, DimSun has the highest effectiveness and affordability among all existing geoengineering approaches. For example, DimSun is 150X cheaper than space-based solar occulter-based methods and 6X cheaper than Stratospheric Aerosol Injection during 21st century.

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