4 ms·

Wouldn't your idea, at best, null-out the forward propulsive force, but not actually decelerate the ship?

• chiph 11y ago
  Not my idea - it's been around for decades. It works because you can treat the two kites as one system, because they're both connected to the ship.
  • gherkin0 11y ago
    > Not my idea - it's been around for decades. > It works because you can treat the two kites as one system, because they're both connected to the ship. Care to supply some citations?
    • chiph 11y ago
      Physicist Robert L. Forward mentioned it in his book Rocheworld (later republished as The Flight of the Dragonfly)in the early 1980's, with the concept work being done in the 1970s. https://en.wikipedia.org/wiki/Solar_sail#Interstellar_flight https://en.wikipedia.org/wiki/Solar_sail#Interstellar_flight
      • gherkin0 11y ago
        That's a science-fiction book, though. I'm still not getting how the ship could basically sail straight into the laser that's pushing it (e.g. decelerate). The main sail is still getting pushed forward by the laser, even while the second sail is pushing backward (with the reflected light from the main sail).
        • chiph 11y ago
          His credentials in the field are pretty good, and his books are always hard-science (no elves or wizards, and very little hand-wavy stuff). https://en.wikipedia.org/wiki/Robert_L._Forward https://en.wikipedia.org/wiki/Robert_L._Forward If I recall the design correctly (forgive me - it's been over 15 years since I read it), there's a significant size difference in the sails. The larger sail collects photons from the distant laser and focuses them on the smaller "backwards facing" deceleration sail.