Arriving within a century is a significant new requirement! But yeah, we haven't done it at all. We've gotten 5 objects to escape velocity to leave the solar system though, so it's not a huge leap to chuck it at Alpha Centauri instead of wherever we did... Of course those things aren't going very fast, the internet says Voyager 1 would take 74,000 years or so to make it to Alpha Centauri at its current speed if that's where it were heading. That's a really long time, so it's not super worthwhile to do. You might be able to design a system to launch a 10kg object from an interstellar probe after it reaches heliopause to get a higher velocity, but it's still going to take approximately forever to get there... And I don't know that we can track our interstellar probes if they're not sending radio signals anyway? So chuck it at Alpha Centauri and make a website that counts down to the day it gets there, cause nobody is going to know if it actually made it there and you'll be dead anyway.