A Visionary Project Aims for Alpha Centauri, a Star 4.37 Light-Years Away
So the whole thing should weigh in the order of several grams, yet it should be able to deflect 100GW of incoming radiation near perfectly (otherwise it will instantly vaporize) while maintaining structural integrity under the acceleration of 60,000g for two minutes?<p>And whatever laser sources we're using must track this smartphone-sized object during these two minutes across several million kilometers.  Perfectly.  (It also means that whatever course deviation the object experiences must be anticipated <i>seconds before it happens</i>, because at the end of the two minutes the object will be ~10 light-seconds away.)<p>If they could pull this off it will be the next Apollo, but I'm skeptical.<p>Edit: Just realized we have even more problems, about the reflective coatings.  If the laser is green, by the time it's flying away at 0.2c, the laser won't be green any more thanks to the Doppler effect!  I'm too lazy to calculate, but it will definitely shift toward the red.  So whatever reflective coating we use must be able to work near-perfectly over a wide range of spectrum.