Is there enough space for thousands of new satellites?

Henning Heiselberg, head of Security DTU, answers questions about the increased satellite traffic in space.

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24 Jun, 2020

Image by Ondřej Šponiar from Pixabay

Image by Ondřej Šponiar from Pixabay

In addition to heading Security DTU, Henning Heiselberg researches and lectures in satellite physics and Earth observation. DTU’s profile magazine Dynamo asked him a number of questions about the many private and state-owned satellites that are planned for launch, especially by the American aerospace company SpaceX.

Q: Why are thousands of satellites being launched?

A: Private companies want to enter the broadband market and launch satellites for that purpose. The biggest player right now is Elon Musk and SpaceX, which with its Starlink project wants to offer global broadband connectivity to all of the world’s populated areas by 2021. 60 Starlink satellites are being launched about every three weeks. According to some reports, Starlink will initially launch 12,000 satellites and perhaps another 30,000 at a later stage. By comparison, about 5,000 satellites currently orbit the planet, about half of which are in use. Other players are Boeing, Amazon and OneWeb, which also plan to launch satellites to enter the broadband market. 

Q: Is there room for them all?

A: No, there’s limited space in the satellite orbit trajectories around the Earth, and we’re already starting to fill up the ones close to the Earth. The nearest orbits are just beyond the atmosphere, at a distance of 160-2,000 km. Starlink has received permission to use these very orbits. Crowded orbits increase the risk of collision with the satellites already up there. This is a serious issue because collisions would create huge amounts of space debris that would pose a threat to the other satellites. The speeds are extremely fast up there, so even though space scrap is smaller than 1 cm, it whizzes along at 20-30 times the speed of sound and can cause enormous damage. In the worst case scenario, we end up with space becoming useless.

Q: Will the satellites have unintended consequences for us here on Earth?

A: Yes. Around sunrise and sunset, we’ll get thousands of new small, twinkling stars moving at full speed across the sky as the sun’s rays hit the satellites. Astronomers exploring the universe with ground-based telescopes will see this as light pollution of the night sky. Another problem is the radio waves that will be emitted, which will make ‘noise’ 24/7 and may for example prevent researchers from using passive radar to measure and observe ice and seawater.

Q: Is it just first come first served in space?

A: In a way, yes. There’s no overarching international authority regulating access to satellite orbit trajectories. Access is primarily controlled by those who can afford it. It’s hard to regulate it at an international level, because there are major political and economic interests at work.

Q: What is the driver behind this development?

A: Falling prices. It’s become much cheaper both to mass produce satellites and to launch them. In part because of Elon Musk’s influence, the cost of getting into space has fallen by a factor of almost ten. So space has suddenly come ten times closer. That’s where he’s been a pioneer. He and the other players do it because there’s a business opportunity there. After all, we all want to have access to broadband wherever we are on Earth. When we’re in a new place, the first thing we ask is “what’s the Wi-Fi password?” So the satellites serve a beneficial purpose, because they facilitate communication for us here on Earth.

Q: What does this mean for the militarization of space?

A: The lower prices of satellites and access to space have also affected military use, with more new and smaller nations exploiting space for military tasks. Even the Danish Armed Forces had its first CubeSat, Ulloriaq, sent up two years ago, which will be used to monitor ships and aircraft in the Arctic. So now the big nations with advanced space technology do not have space all to themselves anymore. Right now, we’re in a phase where there’s increasing awareness of the military use of space. Some nations have launched satellites capable of capturing space debris, but they can also be used to capture other nations’ satellites or spy on them. Most recently, Donald Trump has launched the US Space Force and US Space Command, but this is mostly gesture politics, as the US has held technological hegemony in space for decades.

Q: Should we be concerned about the increased militarization?

A: It depends on how nations behave. The big picture is that technological advances in space benefit us all. We have satellites that give us precise GPS coordinates down to the centimetre, we have satellite TV, internet, telephony, weather forecasts, and climate monitoring. In fact, we should turn the question around: it started with the militarization of space, which went on to become more of a ‘civilian’ use of space. It’s more a case of an increased civilization of space.

24 Jun, 2020

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