The Y Que was a small racing ship owned and crewed by Manéo Jung-Espinoza, who spent months building it from salvage. It was not outfitted with an Epstein Drive, and had its transponder removed to maintain radio silence. The english translation of the spanish Y Que is And What.
The ship was used by Jung-Espinoza to "slingshot" from the Belt to Uranus's orbit, to ultimately reach and fly through the Ring. Although he was successful in this, the slow zone on the other side of the Ring caused the pilot's death, and the Y Que came to rest in orbit around Ring Station together with other debris.
Y Que is Spanish for "and what?". In American-English, the phrase is used as a form of confrontation and in competitive situations as well.