>>5547529Voyager I has the fastest heliocentric recession speed of any spacecraft, at about 17 kilometers per second (11 mi/s). It would take over 70,000 years for it to reach Alpha Centauri at that speed.
The "100 years" figure comes from unmanned, futuristic projects like Project Longshot (
https://en.wikipedia.org/wiki/Project_Longshot).