Problem child for a million years: the UK's Skynet-1A satellite

Recently, the BBC reported as a curiosity of space travel that someone had moved the UK's oldest satellite, Skynet-1A, from its original location, but no one now knows who, when or why. The British authorities responsible are sure to be ridiculed, but the case once again highlights the problem of "space debris".

Originally, Skynet-1A was placed in a geostationary orbit over East Africa (36,000 km high, 40° East), from where it served as a communications relay for British forces. However, this only worked for around a year before the transmitter amplifiers failed, presumably due to insufficient adaptation to large temperature differences. Rarely has the diagnosis "cold solder joint" been more apt in the literal sense. Today, the space wreck is inexplicably located over the west coast of South America at 105° West. That is too close to satellites that are in operation.

False gravity hole

There are some indications that it did not arrive at its current position by chance, but was actively steered there. Without active movement, the wreck would have slipped into the next gravity well over the Indian Ocean as seen from East Africa and stayed there. Instead, it is in the next but one gravity hole near South America. There, Skynet-1A swings back and forth as if in a dish and comes alarmingly close to other satellites up to four times a day. Its minimum distance (Apogee) is 35,784 km, the maximum 35,794 km (Perigee). Today, old satellites and other wrecks are transported to an orbital graveyard even further away from Earth, where they do not endanger any active satellites.

We may wonder about the lack of records today, but Skynet-1A was launched into orbit in 1969, just a few months after the first man set foot on the moon – and at that time no one was concerned about the disposal of artificial space objects. Today, this negligence is costing dearly, as Skynet-1A has long been a danger to other satellites and, according to the UK Space Agency, it will probably remain so for the next million years unless special measures are taken.

The authors of the 1 MB UK Registry of Outer Space Objects catalog believe this to be the case, which is why the British National Space Operations Centre is constantly monitoring its position and movement. As it can no longer move itself due to a lack of fuel, the institute informs the operators of neighboring satellites if a collision course is imminent. In this case, endangered satellites have to avoid the unguided block. In any case, a collision must be avoided at all costs, as this creates a lot of small and fast debris (super-spreader events), which can literally shoot down many other satellites.

Space cleanup

Although methods are currently being developed to fish debris out of orbit, the silenced relay is likely to orbit the sun with the Earth for quite some time before the technology is ready for Skynet-1A. The British Space Agency is already gaining experience with objects in lower orbits. So far, only the USA and China have shown that geostationary space debris can also be disposed of.

The British government has launched a competition to find solutions for the disposal of orbital debris. The winner is expected to present their proposal at the end of 2026 or beginning of 2027. Interesting methods are being developed by the Swiss company ClearSpace and the Japanese company Astroscale, for example. According to Astroscale's idea, a satellite equipped with a robotic arm could be sent into space to grab wreckage and guide it towards the Earth's atmosphere, where it would burn up.

The German company OHB is working with ClearSpace on its own process as part of the ESA's ClearSpace-1 mission. This involves a space tug with four arms picking up disused satellites and also ejecting them into the atmosphere.

(dz)