Oldest UK satellite goes rogue

The UK’s oldest satellite was launched into space in 1969 to aid the communications of the British armed forces. Years later, Skynet-1A was decommissioned, and space scientists predicted that gravity would pull it towards the Indian Ocean. But, instead, it appears to have mysteriously been redirected so that it now occupies airspace over the Americas. But no one seems to know why. The space consultant Stuart Eves has been investigating the puzzling progress of Skynet-1A, and he brought me up to speed with what he’s found…

Stuart - When I started researching this, I rapidly convinced myself that there was no realistic prospect, that natural perturbations due to solar radiation pressure, the push that the radiation coming off the sun gives the satellite, would ever be strong enough to overcome the gravitational forces which would leave it oscillating around the Indian ocean. So I concluded that it must have been deliberately moved by firing the thrusters on the satellite itself, but by whom and when wasn't at all clear.

Chris - When did someone notice it was in the wrong place then Stuart?

Stuart - I think that was probably me. We are required as a nation to inform the United Nations of the locations of all the stuff that we have put into space. And because it's our oldest satellite, the first entry in that registry is Skynet-1A. It's location on the geostationary ring says 105 West. And I looked at that and thought, well surely that's not right. I was pretty confident that the satellite had operated somewhere near 40 degrees east when it was operational. And as you'll readily appreciate, you can't even see 105 degrees west from the UK because it's too far around the planet. So <laugh>, it initially looked as if there was some sort of mistagging or error in the catalogue, but over the time of my investigation I've become more and more convinced that the thing that is 105 west really is our satellite and that's why it's puzzling as to how it got where it is.

Chris - How do you think it did get there?

Stuart - So as a result of some of the publicity that this story has generated recently, I have found some additional information which seemed to confirm that the satellite was actually manoeuvred in 1977. So that's considerably after the information that I'd been able to find. I found reports that were created by what's known as the Royal Aircraft Establishment at the time and they went up to the end of 1973 and then the trail went very, very cold. And I think that's probably around the time when the satellite stopped providing a useful function, the actual communications payload probably wasn't working. So I think the satellite was still capable of receiving commands to do things like make manoeuvres. And as far as I can tell, in 1977 a decision was taken to actually move the satellite across the Atlantic. And I'm fairly confident that both the UK and the US must have been involved in the decision to actually do that.

Chris - So someone would've known, probably multiple authorities would've known, but they just kept quiet and they didn't update the official register. That's what you are contending. Why on Earth would someone want to do that with a defunct satellite? It argues there was some other reason for wanting to park it back over the Americas.

Stuart - So it's possible that the satellite was transmitting on a frequency that was causing some form of interference and that they wanted the frequency clear for other satellites to use. So they decided to kind of move it out of the way to avoid the radio frequency interference. The other hypothesis that I have is that you have to remember that we're in the very early days of geostationary satellites. Technology is not well developed. A lot of the subsystems on the satellite would've been flying in space for the first time. And it's possible that although the UK didn't have much utility for the satellite because it wasn't providing a useful communications function anymore, it's possible that its builders over in the United States might have thought, well it would be quite interesting to see how the different bits of the satellite, you know, the batteries and various other subsystems are standing up to the radiation environment in space. So they might have been quite keen to sort of have it back and be able to watch how it degraded over time and how long it lasted.

Chris - And I was hoping you were going to come up with something a bit more X-Files than that.

Stuart - So it is quite interesting that the sort of advertised function of the satellite was definitely about military communications for UK forces. But there are bits of documentary evidence in various books and things that I've been able to find that suggests that GCHQ was also making use of the satellite. Today if you launch a geostationary satellite, you were assigned a particular location, essentially assigned a particular longitude. And it's your job as satellite operators to sit your satellite at that longitude and not move around too much because potentially you'll cause interference if you drift backwards and forwards. But there was very little else in geostationary orbit when Skynet-1A was operational and it was allowed to drift backwards and forwards by up to about 20 degrees at times. That aspect of it would've been quite consistent with GCHQ using the satellite to try and work out where various foreign transmitters were, for example.