Cerise — first confirmed accidental collision (July 1996)

On 24 July 1996, the French military satellite Cerise was struck by a catalogued piece of space debris — a fragment from an Ariane upper stage that had exploded a decade earlier. The impact severed Cerise's gravity-gradient stabilization boom, and the event became the first verified accidental collision between a catalogued debris object and an operational satellite.

A warning, two decades early Cerise survived the strike — controllers adapted to the loss of the boom and kept the satellite working — but the collision was a stark, concrete demonstration of a risk that had until then been mostly theoretical. It showed that the growing population of catalogued debris could, and eventually would, hit working spacecraft.

Context The collision predated the much larger 2009 Iridium 33 / Cosmos 2251 collision by thirteen years. Together the two events bracket the era in which orbital debris went from a modeled concern to a demonstrated operational hazard.