The unmanned aircraft (destined to become the Navy's first "killer drone") completed a series of tests, which included a catapult launch and arrested landing. These tests demonstrated its ability to operate safely and seamlessly with manned aircraft.
After hitting some important milestones, the next step was to occupy the carrier pattern with the manned aircraft in order to test whether the UCAS is able to land and vacate the landing area within the time lines that are required for blue water ops aboard a U.S. flattop.
According to the U.S. Navy:
The first series of manned/unmanned operations began this morning [Aug. 17] when the ship launched an F/A-18 and an X-47B. After an eight-minute flight, the X-47B executed an arrested landing, folded its wings and taxied out of the landing area. The deck-based operator used newly developed deck handling control to manually move the aircraft out of the way of other aircraft, allowing the F/A-18 to touch down close behind the X-47B's recovery.