Have you ever camped somewhere quiet? Pitched your tent, carefully lit a small fire, watched the stars appear as the sky goes dark, picked up your phone to ask the internet if that’s Venus you can see – and then realised there’s no signal? With several private companies racing to develop the first operational space-based WiFi network, this could soon become a thing of the past – but so might your view of the stars.
Since the 1950s, humans have been launching satellites. From the early days of the space race the technology has developed dramatically, with satellites today carrying out tasks from communication to earth observation, measuring everything from ice coverage and wildfires, ocean currents and weather, to enabling the tracking of land use changes, predicting droughts and spotting leaks from gas pipelines.
Arguably, the next logical step is a network of satellites providing global, universal internet access, and many companies are working on developing exactly this. These networks of satellites, known as constellations, will provide relatively cheap, low-latency and accessible internet to anyone on Earth. This will be particularly beneficial for remote locations where the potential benefits of internet access would be significant for human and economic development but cost of installing fibre is prohibitive.
Affordable, universal internet coverage enables fast, reliable communication, transcending socio-political boundaries, bridging the digital divide and helping people everywhere access education and reducing global inequality.
Is there space in space?
There is clearly huge potential, and lots to be gained. But is there enough room in low Earth orbit? According to data maintained by the UN Office for Outer Space Affairs, there are currently 4,655 satellites in Earth orbit, though less than half are operational. In total since the 1950s, humanity has launched more than 9,500 satellites into space. The number of objects launched in a year doubled between 2016 and 2017, and in 2020 we have already (as of June) launched 562 objects, almost as many as in the whole of 2019. Including debris fragments, there are over 23,000 objects larger than 10 centimetres in size currently orbiting the Earth.
Space may be big, but the available space in Earth orbit is finite. Satellites have to avoid each other, they must communicate with other satellites in their networks and with those on the ground without interfering with each other, and we need to know accurately where they all are to avoid collisions. These are significant challenges; the safe use of Earth orbit requires cooperation.
Each of the companies developing these networks is planning and launching its own constellation, consisting of several hundred (and up to tens of thousands of) individual satellites. If we want to provide cheap, accessible internet to every community, then we will need to safely launch and operate many tens of thousands of satellites. How do we ensure this is done in a sustainable way?
The UN Committee on the Peaceful Uses of Outer Space produced guidelines on the sustainability of outer space activities, covering the avoidance of contamination (both of other planets and of the Earth), the safe re-entry of defunct satellites, sustainable use of the (finite) radio spectrum, the sharing of space weather and forecasting, among other things. However, these guidelines are voluntary. Going forward, and in order to protect both the space around the Earth, the safety of the people on it and their view of the universe, we need international cooperation and agreement.
Blinded by the light
What about that view of the stars from our campsite? In good conditions we can see a total of around 10,000 stars with the naked eye, spread across both hemispheres. The darker your location, the more stars you can see. Over time our night skies have become brighter and brighter, with every new streetlight or security light making the stars harder to see. As a consequence, astronomical telescopes are confined to remote places, often on the tops of isolated mountain peaks.
However, this dramatic increase in satellite numbers now threatens these facilities and the science they enable. New constellations are launching at a time when several large, multi-country, expensive telescopes are under construction or becoming operational. The problem with the proliferation of satellites is that it becomes impossible to avoid them when trying to observe the universe. At least one of these companies is working with astronomers to try to minimise the effects on observations, but there is no regulatory compulsion to do so. The big science questions these telescopes were built to address will become impossible to answer if we can no longer see the sky properly.
One telescope at risk is the Vera C. Rubin Observatory, a large optical telescope with a 3.2 gigapixel camera under construction in Chile, which aims to rapidly scan the sky to search for transient astronomical events and asteroids, among other things. This telescope should see first light this year, but will be particularly adversely affected by the extreme photobombing caused by large numbers of satellites passing through its large field of view.
It isn’t just optical telescopes that will suffer, either. For current and future radio telescopes, the proliferation of transmitters in orbit will make trying to observe the universe like trying to hear a violin over the sound of a jet engine. The cosmos will become as invisible to radio telescopes as the stars are to the human eye during the day.
Now, no astronomer is arguing against the human and economic benefits of universal internet (astronomy itself is being used as a basis for development projects around the world), but there is concern that this will ruin the view for everyone, and render much of modern astrophysics impossible in the long term. This ultimately leads to a waste of taxpayers’ money, a loss of training opportunities in the high-level technical and analytical skills that astronomy provides (most astronomy graduates do not become astronomers, but work in IT, business and the civil service, where they put those analytical skills to good use), and a loss of part of our shared cultural heritage.
One solution is obvious: we could just send all our telescopes into space. That's fine if you have the money to do it, and it does happen (the Hubble Space Telescope being the best-known example). In practice, this is always a more expensive option, it is a lot more risky, if something goes wrong it is difficult to fix, and you can't build your telescopes as big for the same amount of money. This may be the long-term future of astronomy, but we are a long way from that being normal. It also does nothing for the view from our campsite.
For the moment, these constellations are being launched only with the go-ahead from US agencies, but they impact the whole planet's view of the universe. The night sky and the space around the Earth can (and, perhaps, should) be thought of as a natural wilderness and protected as such for everyone to enjoy and use, but that requires serious international cooperation and agreement – which, at present, does not exist.
Having internet access can drive economies forward and provide an excellent gateway to education. Is protecting the night sky for the minority of those who want to look at it (including amateur astronomers and children) more important than providing affordable internet in remote areas? Definitely not, but if we want to preserve the night sky for future generations, we need to act now. After all, if we can’t see the sky, we might not find the next incoming asteroid until it’s too late.
Megan Argo has a PhD in Radio Astronomy from the University of Manchester and is a Lecturer in Astrophysics at the University of Central Lancashire. She sits on the grant review panel for the International Astronomical Union’s Office of Astronomy for Development.