No Borders in Space
Adam Kall, Director of Science
4 minute read
"I really believe that if the political leaders of the world could see their planet from a distance of, let's say 100,000 miles, their outlook would be fundamentally changed. The all-important border would be invisible, that noisy argument suddenly silenced." - Michael Collins, Apollo 11 Command Module Pilot
Most astronauts remark that, once they get into space, the divisions on Earth become far less apparent and it really looks like one whole of humanity. This viewpoint is for a variety of reasons. Possibly because things like border walls and crossing checkpoints are too thin to be viewable from space, or that the land isn’t conveniently colored like the maps and globes we grew up seeing in school. I would add another reason to the list, and that is that because of orbital dynamics it is not possible to effectively secure a region of space as belonging to any one country. I hope you’ve been reading our Space Terms series, because I’m going to be using a lot of terms from there to describe why orbits are always international and what therefore are the implications.
Every nation has a concept of controlled airspace and national airspace. Controlled airspace are regions that require specific procedures from pilots, like the areas around airports and major cities. National airspace is a concept that a nation owns the air above its territory and can approve or deny aircraft the right to fly through it. There have been many moments when one nation’s armed forces will enter another nation’s airspace without permission by flying over it, often to the loud complaints of the offended nation as well as international disapproval. A famous example is the 1960 CIA U-2 flight, piloted by Francis Gary Powers, over the USSR. The program had started in 1956 with the idea of flying a spy plane so high it wouldn’t be detected by radar, and so the USSR wouldn’t know their airspace was being violated. However, the planes were detected and in 1960 one was shot down and the pilot captured alive. During the height of the Cold War, one would assume the USSR firing a missile and destroying an American aircraft would be seen as an act of war. However, it was the flight into USSR airspace that was seen as a potential act of war, and the destruction of the aircraft a natural reaction by the Russians to an unapproved overflight.
One hundred thirty three countries have signed the International Air Services Transit Agreement, which allows commercial airlines from agreeing nations to fly over any other nation in the agreement without landing. The notable exception is Russia, which has the largest territorial landmass of any nation and therefore the largest airspace of any nation. Russia has been able to use their airspace as a diplomatic weapon, threatening to block all aircraft from western nations if they don’t lift sanctions or perform some other politically advantageous act. And yet, while they make these threats, up to a dozen astronauts from all over the world pass overhead daily, alongside thousands of satellites and pieces of debris. The only consistent reason Russia allows this is because the laws of physics mean there is no practical alternative.
Getting into orbit consists of using some energy to go up and get above the atmosphere, but a lot more energy to go sideways to outpace the approaching ground. The sideways speed necessary to maintain orbit is decided by a simple mathematical formula that only takes the altitude as an input, which means orbital speed limits are absolute. If the International Space Station wants to orbit at 400km above the Earth’s surface, it has to travel horizontally at 17,180 miles per hour exactly. Considering that the Mainland of the U.S. is less than 3,000 miles across in a straight line, it should be clear that things in Low Earth Orbit (LEO) do not stay over one country for very long. This then leads to the question that if a satellite can’t stay over one country, can it specifically avoid a country?
Using Russia for this example as the target country to avoid orbiting over, its landmass exists from as low as 42 degrees North and as high as 77 degrees North. This means any satellite with an inclination of greater than 42 degrees will eventually cross over Russian territory, since an inclination of higher than 77 degrees would have to cross that region to get there. It is also important to remember that satellites are very high up, so if the concern is not just whether a satellite travels above the nation’s land, but also if it can see into the land, then the safe inclination is reduced further to only 22 degrees at an orbit of 400km, and at an orbit of 2,000km, or the edge of LEO, there is no orbit which won’t be able to see some of Russia. This is also not taking into account the fact that many other countries share these latitudes, so a satellite which needs to pass over the U.S. will inevitably also pass over Russia, and vice versa. It was actually the first satellite, Sputnik, which proved this to the world as it passed overhead, and anyone with a radio could pick up its iconic beeping message.
Fast forward to the modern day and everyone has come to accept that satellites will pass overhead as a part of regular life, yet a threat looms that reverts thinking to the idea that it will only be an issue for some other country. Orbital debris objects are generated through the regular activities of space flight and they slowly spread over a wide range of inclinations and orbits, to the point that no orbit is spared and no country avoids having some orbital debris passing overhead. In addition to the very real risk of in-orbit collisions, this is also causing an issue of light pollution for astronomers, with an ever increasing number of bright streaks across their images of the heavens. It is reasonable to think that the organizations responsible for this debris should be required to clean it up, but this approach ignores the risk everyone faces from the debris. It is less about who caused the problem, but who is most impacted by it. For the problem of orbital debris, it impacts every spacefaring nation, and any nation which benefits from the services of space.
Recommended column to read next: Space Traffic Management and Defense