The orbit is already buzzing with Starlink satellites. Along with greater connectivity, it also comes at the cost of space pollution. With China set to build a Starlink-style satellite constellation, astronomers warn that the night sky may soon become unrecognizable.
When the first batch of 60 Starlink satellites was launched by SpaceX in May 2019, people turned out to watch in their thousands, and the technology was a novelty for quite some time.
Now, the company is the world's largest satellite operator, with more than six thousand satellites currently in orbit – and eventual plans for as many as 42,000.
However, all this presents problems in the form of debris and potential collisions. Starlink satellites, says SpaceX, were forced to make nearly 50,000 collision-avoidance maneuvers in the first half of this year, double the number for the previous six months.
And of course, the Starlink network is itself part of the problem. According to research from the University of Málaga, low-Earth orbit can only hold about 72,000 satellites before collisions between them produce so much debris that Earth’s orbit becomes unusable – the so-called Kessler syndrome.
Chinese plans
Soon, the problem will get dramatically worse. This summer, China launched the first 18 satellites of its own broadband constellation, Qianfan, with plans to expand it to 14,000 satellites by the end of the decade.
And it's causing problems already. The initial launch, according to space-tracking and data analytics firm Slingshot Aerospace, saw the break-up of the upper stage of the rocket delivering the satellites to orbit, creating more than 50 pieces of space debris.
"If even a fraction of the launches needed to field this Chinese mega-constellation generates as much debris as this first launch, the result would be a notable addition to the space debris population in LEO," warned Slingshot Aerospace vice president of strategy and policy Audrey Schaffer.
"Events like this highlight the importance of adherence to existing space debris mitigation guidelines to reduce the creation of new space debris and underscore the need for robust space domain awareness capabilities to rapidly detect, track, and catalog newly launched space objects so they can be screened for potential conjunctions."
The World Economic Forum (WEF) recently weighed in on the topic with a call for greater information-sharing between satellite operators and the organizations that monitor the location of objects in orbit and warn of potential space collisions – what's known as Space Situational Awareness (SSA).
Perhaps astonishingly, no global agreed-upon system for coordinating space traffic currently exists. Satellite operators manage their satellites entirely independently, and there are multiple different sources of relevant safety information.
"Often, satellite operators have precise and timely information about the location of their own spacecraft," says Richard Dalbello, director of the Office of Space Commerce, and Mariel Borowitz of the Sam Nunn School of International Affairs at Georgia Institute of Technology.
"Sharing this information with SSA providers can improve the accuracy of collision warnings. Satellite operators can also provide advanced warning of their planned maneuvers in orbit that would be difficult or impossible for others to predict in advance."
The WEF says SSA data and information should be made open by default, and spacecraft owners or operators should share up-to-date contact information, maneuver plans, and spacecraft characteristics via SSA providers.
Meanwhile, government SSA providers should share conjunction warnings, and information about their satellite catalogs and sensor observations.
Astronomers increasingly worried
Satellite constellations are causing other problems too – again, with Qianfan likely to make the problem much worse.
In a recent paper, researchers point out that the design of these satellites, featuring a large flat-panel antenna, makes them exceptionally bright: magnitude 4 when overhead, and magnitude 8 when low in the sky. This, they point out, is more than the magnitude 7 limit beyond which there's interference with astronomical observations.
"These satellites will impact astronomical research and aesthetic appreciation of the night sky unless their brightness is mitigated," the researchers warn.
And it's not just a question of visible light. A study using the LOFAR radio telescope in the Netherlands recently showed that the most recent V2-mini Starlink satellites emit unintended radio waves that are up to 32 times brighter than the previous generation.
And while SpaceX made changes to the design of its original Starlink satellites thanks to similar concerns, it's unclear whether it will do the same this time – and whether China can be persuaded to follow suit.
Another concern is the environmental damage caused when satellites come to the end of their lives. Starlink satellites, for example, are designed to last only five years, after which they leave orbit and burn up in the atmosphere.
And, says non-profit the Public Interest Research Group (PIRG), scientists are worried about conductive particulates from burnt-out satellites lingering around in the atmosphere, with pollution potentially damaging the ozone layer.
International efforts
While low-Earth orbit still has much in common with the Wild West, efforts are taking place to monitor satellites in a more coordinated way.
For example, in 2027, the UK and Canada plan to launch the Redwing microsatellite Space Domain Awareness (SDA) mission. This mission will use the latest sensors to track objects in congested orbits and provide near real-time information on space events.
"Space is increasingly congested and it is vital that we keep pace with new and emerging threats," says Dr. Gemma Bagheri, space research and development program manager at the UK’s Defence Science and Technology Laboratory (Dstl).
"The collaboration with our Canadian partners will enable us to improve the characterization of objects and maintain security in space to protect our mutual interests."
And, earlier this year, ten countries signed up for the European Space Agency (ESA)'s Zero Debris Charter, promising to become debris-neutral by 2030.
"To implement the Zero Debris Charter, ESA will focus on developing ground-breaking technologies for satellite end-of-life disposal, in-orbit servicing, and active debris removal," said ESA director general Josef Aschbacher at the launch. "The Zero Debris Charter is just the beginning, the starting point of our ambitious, collective capacity-building activities."
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