The May 1 Space-X launch of a classified satellite mission was considered very unusual after amateur satellite watchers realized it was being put into the same orbit as the International Space Station (ISS).
(ISS resupply missions aren't classified.)
We now know that not only was "USA 276" put into the same orbit, but it actually buzzed the ISS as it gradually "orbited" around the space station.
Here's a simulation from the SatTrackCam blog, showing the new spy satellite just outside the box representing the safe distance for objects to pass near the ISS without an orbital avoidance maneuver:
SatTrackCam blog simulation of the close approach of USA 276 to the International Space Station on June 3, 2017.
Over time, the spy satellite then circled the ISS, just several kilometers away.