> synchronizing probes’ on-board clocks with Earth and with each other to support accurate position-navigation-timing (PNT). Damn, at first glance at least, th

> synchronizing probes’ on-board clocks with Earth and with each other to support accurate position-navigation-timing (PNT). Damn, at first glance at least, this seems like a hell of a challenge when they're talking about travelling at relativistic speeds. Also, what about deceleration? Do they flip the sails around at some point to get slowed down by the stars light?