Home Electromagnetic SpaceX against astronomers: Starlink in the telescope’s sights

SpaceX against astronomers: Starlink in the telescope’s sights


Elon Musk, whom no one has accused of being timid and retiring from his businesses, is engaged in deploying what he hopes will be some 40,000 satellites in low Earth orbit to form what he calls a Starlink system to provide Internet service to the served sub-regions of the globe, and also presumably to earn money.

So far, several thousand mass-produced satellites have been launched in batches of dozens at a time, although a recent geomagnetic storm has caused some of the newer ones to die out early, as the resultant denser atmosphere at their orbital heights dragged them to a fiery death.


The satellites are relatively small – around 500 pounds (220 kg) and about the size of a table – and burn up completely when they de-orbit, so we don’t have to worry about pieces falling on our heads.

But those who worry about those who remain in orbit are astronomers, who already see small bright spots from the Starlink satellite crossing the field of view of their telescope, especially when they try to observe near the horizon at the dusk or dawn.

For some time now, astronomers have been trying to draw attention to their plight, which is only getting worse as other commercial space companies compete with Musk’s company SpaceX for market share. communication satellites in low earth orbit.


Last week, the International Astronomical Union (IAU), a sort of UN of astronomy, announced the organization of the Center for the protection of dark and silent skies against interference from satellite constellations. For once, the name of the new organization does not form a pretty acronym, which perhaps testifies to the seriousness of the company.

The reason they call it both dark and calm is that communications satellites, by nature, emit electromagnetic waves, usually in the microwave radio spectrum. And although astronomers have protected bits of the electromagnetic spectrum in which no radio emissions are allowed, these are usually fairly narrow slices surrounded by wide bands where communications-related emissions are permitted.

Delicate technology

Radio telescopes use the most sensitive and delicate radio receivers on the planet, and they are not designed to reject nearby out-of-band interference very well. If one of the Starlink satellites sweeps into the narrow beam of a radio telescope, the satellite’s emissions may interfere with the astronomy receiver in unpredictable ways.

And of course, visible light telescopes easily detect Starlink satellites, even if the satellites are painted black. A recent report in The Independent (UK) says astronomers have their visible light exposures disrupted by Starlink tracks on average once every ten days.

So far the problem is at a manageable level. But multiply it by ten or more, and only Starlink satellites will seriously interfere with many astronomical projects, including the search for killer meteorites that could prematurely end not only Starlink, but everyone who might use it as well. . .

Competing interests

It’s an interesting problem in engineering ethics, if you want to see it through that lens. In that corner you have the public who would probably love internet access but live too remote for that now, and SpaceX who want to provide that service with Starlink. And in that corner you have the IAU saying that what Starlink and similar companies are doing could wreak havoc on much of their business.

Historically, when there is a conflict between an entire industry and another popular institution such as astronomy, a third party such as a government or an international organization must become involved.

This is how radio astronomers got their reserved slices of the electromagnetic spectrum, by advocating for them with the International Telecommunication Union (ITU) and making effective arguments, possibly with a bit of political diplomacy.

Now that the commercialization of space has been going on for at least two decades, we are witnessing the kinds of conflicts that led to the formation in earlier years of the ITU for radio. While no one “owns” the region of space in low Earth orbit in an exclusive sense (“it’s my two quadrillion cubic meters and you can’t send your satellite there”), it is clearly a finite resource, much like the electromagnetic spectrum, and we now see a growing need for some sort of global regulatory body to adjudicate on issues such as the one that has arisen between SpaceX and astronomers, represented by the IAU.

International regulations

Something similar happened when transoceanic flights became routine and different countries had to organize protocols for the use of flight routes and standards for international airports. The International Civil Aviation Organization (ICAO), whose current incarnation dates back to 1947, was born as an integral part of the United Nations to fulfill these functions.

The UN currently has a few branches dealing with space: the United Nations Office for Outer Space Affairs and a register of objects launched into orbit. But none of these companies seem to have the regulatory clout to handle disputes between a brash private company bent on networking the Earth with 40,000 satellites, and a group of scientists with little money to lobby and whose the main argument is that if you overcrowd our telescopes, there’s a tiny chance we’ll miss seeing a meteor that will swoop down on us and destroy civilization.

So far, astronomers simply have to deal with the problems Starlink causes them on a case-by-case basis. And ultimately, it’s entirely possible that most cutting-edge observational astronomy will move to space anyway, as the recently launched James Webb Space Telescope promises to beat anything you can do with it. terrestrial telescopes.

As a global culture, we can see that turning the night sky into shimmering collections of satellites and ruining them for astronomy is a reasonable price to pay for letting the world’s most remote tribe broadcast SuperBowl C live (100, if you’re rusty on your Roman numerals). But if that happens, I think we will have lost something that will be difficult to recover.

Republished with permission from Engineering Ethics Blog.

Karl D. Stephan earned the BS in Engineering from the California Institute of Technology in 1976. After a year of graduate school at Cornell, he graduated with the Masters degree in Engineering in 1977… More by Karl D. Stephan