The discovery of rings of Uranus is generally accepted to be on 10 March 1977 by by James L. Elliot, Edward W. Dunham, and Jessica Mink. That’s 40 years ago today and I mention “generally accepted” because the great William Herschel claims to have seen rings around the planet and who knows maybe he did because in his notes in 1789 he noted a ring was suspected (see “Uranus rings were seen in 1700s“).
I’m sticking with 1977 and that by the way, is a great story because at the time the trio were actually in the Kuiper Airborne Observatory planning on seeing the planet occult a star (SAO 158687). Read the story.
Much more about Uranian system can be found at our site with some great mystery questions at the end. No missions are scheduled, pity, much to be be learned.
The picture at the top (and you should click it to make it a bit larger) gives an annotated view from Hubblesite from 2005. In 2007 the Hubble took images of the rings edge on and the last time we “saw” the rings edge on, we did not even know they existed. Look how wide they are: