The engine would be in orbit, producing a beam of photons. The spacecraft would not have to carry that mass along.

Ask ten engineers for the best orbit for a particular spacecraft and you'll get ten different ideas.

Man is the best computer we can put aboard a spacecraft, and the only one that can be mass produced with unskilled labor

Life is 440 horsepower in a 2-cylinder engine.

Indeed, the asteroid's orbit is particularly attractive for spacecraft rendezvous, and the extraordinary close encounter in April 2029 provides a unique opportunity to investigate a number of scientific NEO issues.

We haven't found an exact solar system analog, which would have a circular orbit and a mass closer to that of Jupiter. But this shows we are getting close.