Brian Weeden is the Technical Advisor for the US Secure World Foundation, which promotes the peaceful and sustainable use of space. He is currently the chair of the World Economic Forum’s Global Agenda Council on Space Security.
Brian Weeden says that debris and a growing demand for radio frequencies threaten our future in space. The interview is part of the Risk Response Network’s “What if?” series.
What does this question mean? Isn’t space unfathomably vast?
Yes, but the space around our planet is increasingly congested. Fifty years ago, the era of space exploration began with just the US and the Soviet Union, which were primarily going up there for military reasons. Today, more than 50 countries operate at least one satellite, and there are also all sorts of private entities conducting activities in space. We have a much greater diversity in who is using space and for what, which throws up various challenges.
How does congestion cause problems in space?
One issue is debris. We have all this stuff up there: about 1,000 active satellites along with 21,000 pieces of debris bigger than 10 centimetres, and half a million pieces down to about 1 centimetre, all hurtling around at speeds of up to 25,000 kilometres an hour, which means even the small ones are capable of causing huge damage. Even though space is massive – just from here to the geostationary orbit 36,000 kilometres away, you are looking at trillions of cubic kilometres of volume – the satellites and debris are concentrated in certain areas. We are doing a better job now of creating lower amounts of debris, but we still have this huge legacy amount of junk out there.
The second problem is another type of congestion, this time of radio signals. All those satellites are communicating on radio waves, but there is a limited spectrum for that, just as your neighbours’ Wi-Fi hotspots compete for the same spectrum as the one in your house. The geostationary orbit, which is called that because satellites in it move around the Earth at the same speed as the Earth rotates and so appear not to move, is particularly in demand. It is divided up into slots, so you don’t have too many satellites interfering with each another’s bandwidth, but we are running out of slots, especially over America and Asia. If you talk to satellite operators, they say the biggest threat they face is radio frequency interference, whether intentional or unintentional.
Why do these issues worry you so much?
Space is woven into the fabric of everyday life in ways few people realize. For instance, GPS satellites have very precise atomic clocks on board which broadcast the time. It turns out that there are a lot of things that can benefit from really accurate clocks: over the last couple of decades, they have been used not just for navigation but also to set time for everything from electrical power grids to financial transactions. You are not going to lose the whole signal overnight, and work has been done on backups, but you are still looking at potentially widespread effects if there is a loss or degradation to that timing signal.
What warning signs have you seen that debris poses a threat?
One is that the people who operate satellites increasingly have to take measures to stop them from possibly colliding with debris: in 2011 alone, there were about 150 such manoeuvres. Debris wasn’t really considered to be an issue until 2009, when an active US satellite smashed into a dead Russian one, creating about 2,000 new fragments. The problem is that we don’t have the technology to know for sure when two things are going to collide. The near misses don’t get reported, but they are out there. The rate of these manoeuvres has also increased for the International Space Station, which has six human beings on it at all times. Twice in the last year or so, the warnings have come too late and the astronauts have had to put on their space suits and get into their escape vehicle just in case.
And what about interference?
In addition to satellites possibly interfering with each other, there is also the issue of ground networks interfering with satellites. Recently, an American company called LightSquared wanted to set up a new high-speed wireless service, using a frequency range very close to the one used by GPS navigation satellites. Everywhere they were going to put up their towers, it would have blocked out the GPS signal in the local area. The US government eventually prevented them from proceeding, but only after a protracted legal battle – and this is not the only case. As the competition for terrestrial bandwidth intensifies, there will be knock-on effects in space. Then there is the fact that anyone can go on the Internet and buy a GPS jammer for US$ 1,200. We have seen recent cases of the GPS used in airports going wonky because a truck driver who had bought a jammer to stop his company keeping tabs on him had pulled in for a sleep nearby.
These are both examples of unintentional interference. We have also seen intentional interference, whether it’s Iran jamming Eutelsat, the French commercial satellite that beams down BBC Persia, or reports of the US military using various techniques to jam or interfere with adversaries using satellite communications.
If we were to lose space in space, as it were, how would the situation unfold?
The worst case scenario is not that debris is going to make space unusable; it’s just that it will become very costly to be in certain orbits. If the risk of losing a satellite is higher, you make the satellite stronger, which costs money, or you launch more of them because one or more will fail. Although the business case for communications satellites beaming down the World Cup final will hold up, the scientific applications of space might not. Especially in this era of austerity, we see pressure on the use of satellites to monitor climate change, to predict the weather or keep track of war crimes.
If you take the example of GPS for the frequency issue, from a physical standpoint, the service is really robust: there are 32 satellites in orbit, and we only really need 18 or 20. However, the signal itself, especially the civilian one, is really weak, so it is not hard to jam or interfere with it. We could increasingly see individuals, organizations and countries wreaking havoc, whether intentionally or not. This sort of thing is alarming when you think that GPS is increasingly integrated: it’s not just in our phones and our cars, it’s in the shipping, steering supplies of essential goods, and in agriculture, and it’s being used for air traffic navigation and control.
How well prepared are we for this?
We have good guidelines for minimizing the creation of new debris, which are increasingly being followed, but the problem is the legacy of what is already up there. The modelling for the future isn’t good. We are probably already at the point where there is enough stuff up there to keep generating more debris all by itself, as pieces of junk – and hundreds of them are as big as school buses – keep colliding and creating fragments which go on to cause more collisions. The US military has a network for tracking this debris and providing warnings, but there are huge gaps in its coverage because it was originally built for tracking Soviet missiles coming over the North Pole. There are other tracking capabilities operated by other countries around the world, but there are a lot of challenges in cooperating with them.
The frequency problem is even harder to get a grip on. The International Telecommunication Union, which is part of the UN, has done a pretty good job of allocating bandwidth slots, but it does not have the authority to enforce how these slots are then used. No international organization does, with the possible exception, if it came to it, of the UN Security Council.
What other mitigation approaches would you like to see?
For interference, more information about these incidents would help, as things are kept pretty quiet at the moment. Countries might also need to rethink the balance between national security and the services satellites provide before they resort to things like jamming.
With debris, I am trying to persuade the US government and others that, although monitoring may have been done by the US military in the past, it does not have to be done by the military in the future. Historically, it was done by them, but it is about time to take some of the core services that are necessary for safety of everyone’s satellites and give it to someone else, which would make it a bit easier to work with commercial satellite operators or even the Russians and the Chinese, who also operate a lot of satellites. Eventually, I think there is a case for something similar to air traffic control, where you have the military stepping back to focus on the things that are really important for security and intelligence, and someone else handling the public safety and international cooperation portions.
Image: The Perseid meteor shower, which occurs every August when the earth passes through a stream of space debris (Reuters)