Galaxy 15 zombie satellite (2010)

Galaxy 15, known as the zombie satellite, is the Intelsat broadcast satellite that, out of control, drifted for months along the geostationary arc while still transmitting. On April 5, 2010, the satellite, stationed at 133 degrees west, stopped responding to commands. An electrostatic discharge, probably linked to solar activity, was blamed. The satellite could no longer hold its slot and drifted east along the geostationary arc. The trouble came from what still worked: its C-band payload stayed on and retransmitted any signal it received. Each time it approached a neighbor, notably SES's AMC-11, which carried US cable channels, operators had to coordinate transmissions to avoid jamming. Intelsat moved a spare satellite to take over its customers. Galaxy 15 also carried a WAAS (Wide Area Augmentation System) payload, the GPS (Global Positioning System) augmentation system of US aviation. Physics ended it: antennas off-pointed, batteries drained, the satellite reset as designed in late December 2010 and accepted commands again. For insurance, Galaxy 15 is the textbook case of harm without destruction. A loss of control falls under the operator's in-orbit policy if the satellite was covered; that policy says nothing about harm to neighbors. Radio interference breaks nothing, and in-orbit third party liability, written with collision in mind, may not respond depending on its wording. The jammed neighbor bears a revenue loss it would have to pursue on a fault basis, under the 1972 Convention or general law. No public claim of that kind was reported for Galaxy 15.