Kosmos 1867 was launched by the Soviet Union in 1987, the same year as its twin, Kosmos 1818. It had a similar purpose to Kosmos 1818, but Kosmos 1867 operated for 11 months before shutting down.
Since it is in a high orbit like its twin, Kosmos 1867 has succumbed to the pressures of repeated solar heating. As a result, the coolant tubes aboard the satellite’s nuclear reactor have cracked and allowed the release of liquid metal into space.