2. No way to catch it to board it without achieving impossible acceleration.

3. No way to get off of it without achieving impossible declaration.

4. The impossible acceleration and deceleration would use the exact vast amount of energy the concept is supposed to avoid.

5. At .1 C, every molecule and subatomic particle it encounters in interplanetary space becomes part of a lethal sleet of radiation that kills everyone and everything on it and, eventually, erodes the entire ship into junk.

6. At .1 C, a slight adjustment in course turns the ship into a planet destroying kinetic bomb. Hopefully, the planet that gets destroyed is Mars rather than Earth.

7. At .1 C, the particle radiation erodes the entire ship into a relativistic pile of planet destroying junk. Good thing that at that speed, it isn’t hanging around in the Solar System anyway.

Other than that though, the idea has great promise.