Thread by @AeroDork

Beginning in 1967, the Soviet Union placed a series of radar-equipped ocean reconnaissance satellites (RORSATs) in orbit. In order to return useful data, they had to fly quite low...so low that using solar panels would have caused drag that decayed their orbits very quickly.

To save weight, lower drag, and increase usable lifespan, Soviet engineers opted for BES-5 nuclear reactors fueled by uranium-235. They provided 2KW of power per satellite.

But, yeah, putting highly radioactive material in very low earth orbit? Not a great idea.

You can imagine what happened next.

Fast forward to January 24, 1978. RORSAT Kosmos 954, behaving erratically in orbit, reenters the Earth's atmosphere while traveling on a northeastward track over western Canada.

Radioactive debris showers down from the heavens, blown by the wind across a large swath of Canada's Northwest Territories.

Canadian and American military partnered up to track, identify, and recover the fallen debris through a joint program called Operation Morning Light. The terrain was difficult and vast, but 12 large pieces of satellite were ultimately recovered.

Canada would later bill the USSR C$6,041,174.70 for their efforts...of which they only ever paid C$3,000,000.

Some view the Kosmos 954 event as an early symbol of the USSR's failing nuclear infrastructure. Astonishingly, 5 years later, Kosmos 1402 would suffer a similar fate...depositing radioactive debris across the South Atlantic.

@Grimezsz 🇨🇦☄️☢️