Are these probes micro-accelerating the whole time with ion engines? You'd need 4 times the average velocity to cover the same distance*, which means 8 times th

Are these probes micro-accelerating the whole time with ion engines? You'd need 4 times the average velocity to cover the same distance*, which means 8 times the final velocity, which means accelerating from 0 to 8 over 10 years instead of 0 to 1 over 40 years. That means 32x more acceleration over the whole period. No: we won't have that technology in 30 years, nor in 100 years. Maybe, maybe, maybe if you were able to refuel in orbit and strapped a ginormous multi-stage chemical rocket onto the thing in orbit. Maybe. But we're not going to be doing that in 30 years either. * Higher velocities can mean shorter distances though, because your trajectory is less warped by the curvature of space. The biggest time saver would be avoiding time-consuming gravity assists, if there are any (I assume there are, but I didn't download the 500-page PDF).