That comet? 67P/Churyumov-Gerasimenko.
It finally accomplished that goal in August — when Rosetta rendezvoused with the comet and began orbiting around it. But it's not done yet.
Tomorrow, Nov. 12 Rosetta will deploy a small probe that, if successful, will land on the comet — the first time we've ever landed on the surface of a comet (intentionally).
Before Rosetta, we knew comet 67P/Churyumov-Gerasimenko as just a speck of light — as we do most comets. It's hard to really see what a comet is like because comets are extremely small.
But as soon as Rosetta rendezvoused with the space rock last August, it started snapping pictures of the comet, unveiling for the first time the ominously alien, mountainous world, the likes of which humans have never seen before.