Solar sailing is emerging as a promising form of advanced spacecraft propulsion, which can enable exciting new space–science mission concepts. By exploiting the momentum transported by solar photons, solar sails can perform high–energy orbit–transfer manoeuvres without the need for reaction mass. Missions such as planetary–sample return, multiple small–body rendezvous and fast missions to the outer Solar System can therefore be enabled with the use of only a modest launch vehicle. In addition, new families of highly non–Keplerian orbits have been identified that are unique to solar sails, and can enable new ways of performing space–science missions. While the opportunities presented by solar sailing are appealing, engineering challenges are still to be solved before the technology finally comes to fruition.