This is the transfer stage that carried ComSat Minmus II to Minmus. It was originally designed to go into hibernation high over Minmus after delivering the ComSat, to be re-activated and serve as an impactor when a lander was on the surface. However a bad ascent meant too little fuel was left for the transfer stage to perform the orbital insertion. Instead, the ComSat detached and inserted itself into orbit. Shortly afterwards the transfer stage adjusted its trajectory to bring its perikee down within Kerbin so it is destroyed on re-entry. The maneuver was only supposed to use up a portion of the remaining fuel, but we forgot to disable guidance lock on the maneuver node and the RemoteTech Flight Computer ended up chasing the node all over the navball until fuel ran out. Fortunately this did not have an adverse affect on the maneuver and the transfer stage remained on course to intercept Kerbin.
We successfully re-activated the stage probe core with a wake-up signal from ComSat Link-1, which was the only satellite that happened to be close enough for the stage's 500km omni antenna to reach. This allowed us to confirm its trajectory matched our plot and it was on course to burn up and crash into the ocean near the north pole. Thanks to the short 5-minute window of communication we were able to download telemetry and plot its exact landing point.
