File:Proposed heliogyro mission to Halley's Comet.png

English: Proposed design for a heliogyro solar sail spacecraft intended to rendezvous with Halley's Comet in 1986. The design featured 12 blades in two stacks of six, with each blade 8 meters wide and 6.2 kilometers long, deployed and kept extended by rotating the spacecraft. Spacecraft attitude control and steering would be accomplished by varying the pitch of the blades, allowing it to fly into the solar wind. See https://www.centauri-dreams.org/2017/05/05/remembering-the-sail-mission-to-halleys-comet/ for some additional details.