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.wikipedi

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.