Geostorm

Geostorm (also called Heliostorm) is a mission concept to monitor the solar wind for disturbances that lead to geomagnetic storms before they reach Earth. Spacecraft without solar sails, like NASA's Advanced Composition Explorer, provide ~30-60 minutes of warning by orbiting the Sun-Earth L1 Lagrange point. Solar sails would move this point closer to the Sun by counteracting solar gravity with sail thrust, possibly providing 1-2 hours warning. West2000:Yen2004:West2004:Young2007:Mulligan1998