Current threats and future plans
UNOOSA also maintains the UN Register of Objects Launched into Outer Space. To date over 86 per cent of all satellites, probes, landers, crewed spacecraft and space station flight elements launched into Earth orbit or beyond have been registered with UNOOSA.
So, what is the likelihood of another COSMOS 954-type crash happening in the future?
Sam Harbison, Chair of the United Nations Working Group on nuclear power sources in outer space, established in the year after Cosmos 954, explained that countries are no longer using nuclear power sources in Earth orbits because of the rapid improvements in solar panel technology and in order to avoid unnecessary potential releases of radioactive material. “All the nuclear power source satellites presently in Earth orbit were launched during the 1960’s to 1980’s and it is estimated it will be more than a hundred years before the earliest of them will re-enter Earth's atmosphere.”
More recent uses of nuclear power sources have been on probes, landers and rovers on missions that have left Earth orbit. Examples include the Cassini mission to explore Saturn and its moons, and robotic rovers such as the recently launched Mars 2020 Perseverance mission which will reach Mars early next year. There are aspirations to use nuclear power sources to support human colonies on the moon or Mars. “Solar panels are not sufficient for such prolonged missions, at great distances from the Sun,” Harbison said. “They would have to be complemented by rocket propulsion, which is bulky, heavy and expensive. Nuclear power sources will be needed both for the return journey and to sustain human activities on the surface of the Moon or Mars.”