Kosmos 954 - Wikipedia
Kosmos 954 (Russian: Космос 954 ) was a reconnaissance satellite launched by the Soviet Union in 1977. A malfunction prevented safe separation of its onboard nuclear reactor; when the satellite reentered the Earth's atmosphere the following year, it scattered radioactive debris over northern Canada, some of the debris landing in the Great Slave Lake next to Fort Resolution, NWT.[ 1] [ 2] [ 3]
This prompted an extensive multiyear cleanup operation known as Operation Morning Light. The Canadian government billed the Soviet Union for over 6 million Canadian dollars under the terms of the Outer Space Treaty, which obligates states for damages caused by their space objects. The USSR eventually paid 3 million Canadian dollars in compensation.[ 4]
The satellite was part of the Soviet Union's RORSAT programme, a series of reconnaissance satellites which observed ocean traffic, including surface vessels and nuclear submarines, using active radar.[ 5] It was assigned the Kosmos number 954 and was launched on 18 September 1977 at 13:55 UTC from the Baikonur Cosmodrome, on a Tsyklon-2 carrier rocket.[ 6] [ 7] With an orbital inclination of 65°, a periapsis of 259 kilometres (161 miles) and apoapsis of 277 kilometres (172 miles), it orbited the Earth every 89.5 minutes.[ 7] Powered by a liquid sodium–potassium thermionic converter driven by a BES-5 nuclear reactor containing around 50 kg of highly-enriched uranium (over 90% uranium-235),[ 6] [ 8] the satellite was intended for long-term on-orbit observation, but by December 1977 the satellite had deviated from its designed orbit and its flightpath was becoming increasingly erratic.[ 9]
