Electric sails

An electric sail, or E-sail, is a propulsion system that uses the solar wind—a stream of charged particles emitted by the Sun—to push a spacecraft through space. It consists of long, thin, positively charged tethers stretched out in space. When the solar wind particles encounter these tethers, their like charges repel them, creating a force that propels the spacecraft forward. Unlike traditional fuel-based engines, the E-sail harnesses natural solar wind energy, potentially enabling efficient, continuous propulsion for long-distance space travel without the need for large fuel reserves.