Nearly 1 in 3 Starlink satellites detected within the SKA-Low frequency band
26 comments
·August 13, 2025willis936
perihelions
> "When a company transmits on a band they shouldn't"
The source article is quite clear there's no regulatory violations here.
> "Although this IEMR abides by ITU-R guidelines, these intensities are large compared to the strongest astronomical radio sources in the sky and will therefore have the potential to disrupt astronomical observations at SKA-Low frequencies;"
> "The detected IEMR and UEMR are outside of the frequency bands protected for radio astronomy, but are at frequencies of great interest for key experiments for the SKA-Low facility, and at frequencies where RQZ protections at the SKA-Low site are in place;"
rickdeckard
The source states that the UEMR SpaceX causes in this spectrum is currently not regulated but interferes with astronomical observations.
The claim stands whether a regulation will be put in place which will require SpaceX to fix or switch off their (thousands) of satellites polluting the spectrum or the band will simply be handed to SpaceX.
"This UEMR is not currently regulated by the International Telecommunications Union (ITU), the organization responsible for managing and allocating the radio spectrum for various uses"
mlindner
That's about AST Spacemobile, not SpaceX.
jillesvangurp
Mitigation is going to be the name of the game. Whether they like it or not, low earth orbit (LEO) is becoming a very busy place and it's not just SpaceX launching lots of little satellites there. The Chinese are very busy launching their own satellites into LEO. And there are other companies and countries doing or considering the same. Spacex and Star link get most of the attention; but the Chinese are doing a decent job to keep up with them in number of launches. And there are a growing number of companies with LEO launch capability.
Mitigation might have to involve some sacrifices. I don't see how policy is going to be able to mitigate much here. And of course the Chinese are under no obligation to listen to US policy makers. They might have their own debates domestically around this topic and they might be reasonable about the topic internationally even. But building international consensus; or even enforcing what little there is on that front could be challenging.
A more practical approach might be accepting that earth based observations are inevitably going to suffer a bit as the number of satellites grows from thousands to tens of thousands and eventually well beyond that. Luckily we now are able to launch stuff into orbit a lot cheaper. Including astronomy related hardware. That's already happening of course. And otherwise, astronomy is very interesting and cool but mostly it concerns observations about things that are really really far away and not directly relevant to a lot of things on earth. Unless of course the thing under observation is on a collision course with us.
aragilar
A bit, it's 5 orders of magnitude over the required SNR?! From the article: "The authors estimate a lower limit of 93 Jy per beam in the frequency averaged images containing Starlink emission. Considering just 1 mJy of radio frequency interference could mess up an EoR power spectrum integration, this could severely affect SKA-Low EoR science."
jillesvangurp
> the required SNR
Require by who and on what authority?
My point here was not to contest that but make the point that the cat is out of the bag and that it is indeed impacting SKA-Low EoR science and the people involved with that have to deal with that.
Getting the cat a little bit back in the bag via policy and other means is maybe worth trying (good luck) but I don't give it a very high chance of success.
perihelions
> "The Chinese are very busy launching their own satellites into LEO."
These Chinese (correctly) view these satellite constellations as a key military capability, and have gone all-in on creating their own version. (I mean, I don't see how that's even debatable at that point—having seen the influence of Starlink in Ukraine. Future conflicts will only amplify the gap between the haves and have-nots).
They haven't yet launched a large number (~120); they don't now have the launch volume for large-scale satellite constellations. Their race is to first catch up in launch capability. They have dozen private startups—heavily subsidized and favored by the state—in the race to build a viable, reusable launcher comparable to Falcon 9, that they would then use to launch Starlink-like constellations at the same cadence.
Some starting points:
https://www.wsj.com/world/china/chinas-own-elon-musks-are-ra... ( https://archive.is/Ukmoa ) ("China’s Own Elon Musks Are Racing to Catch Up to SpaceX / Private sector takes bigger role in building reusable rockets, advancing Beijing’s goal of independence from Western technology")
https://www.nytimes.com/interactive/2025/07/23/world/asia/st... ("This Was Supposed to Be the Year China Started Catching Up With SpaceX / It’s looking unlikely. Here’s why")
squigz
Why do we have to launch tens of thousands or even more satellites?
jillesvangurp
There is no royal "we" that "has to" do anything. There's just groups of people and countries making use of a shared resource, LEO.
Your underlying question as to why some of those are launching satellites is much easier. They are apparently quite useful for things like communication, providing internet, etc. And people are willing to pay for that kind of stuff. It's not more complicated than that.
jocaal
Why do we need radio telescopes. Satellite communications are infinitely more useful for people on earth than some research papers about things light-years away
kevindamm
Ironically, those satellites would not be able to communicate effectively without the understanding of relativity that was obtained by looking at things light-years away.
JonChesterfield
This internet fad seems to be hanging around and bandwidth is probably linear in satellite count.
throwaway290
If we had a trusted powerful peacekeeper with a track record then we wouldn't need to. But now that masks are off everybody is busy launching dual purpose sats and whoever launches the least can literally get nuked from orbit if they don't do whatever the guy with more sats wants.
Then whoever has the most sats will say "that's it guys, LEO is full and you need our approval to launch more" and if someone raises a stink you guessed it, they can get nuked from orbit
XorNot
If you think the internet is a big deal, you haven't run into how happy the military is to have high bandwidth low-latency communications anywhere on the planet.
Starlink is nothing compared to the value Starshield provides, and the civilian product drives costs down.
With drone warfare being the next thing, the US probably can't afford to not have a company running a major LEO ISP.
mlindner
"We" don't have to launch anything at all. SpaceX needs to launch enough satellites to satisfy customer demand for their constellation. In general the trend actually is that SpaceX is launching fewer but larger satellites (initially they were doing 60 satellites per launch, but they made them larger and now launch 24-28 satellites depending on the orbit inclination.
nothankyou777
Google says their 8,094 satellites use phased arrays. I wonder what would happen if you directed a few hundred of these phased arrays at a single target?
mlindner
I'm not sure why they're complaining when the SKA isn't even active yet. Once it's active Starlink will do just like they have for other radio telescopes, avoid transmitting while they're in the boresight and in general don't transmit toward the antenna. This is a well practiced interaction at this point with scientific agencies in multiple countries.
The only thing that they can't stop would be things like reflected unrelated ground communications off of the satellite, but that would be very weak.
perihelions
One interesting complication is that it seems the propulsion, the electromagnetic ion thrusters, are one of the sources of unintended emissions,
> "Communication with SpaceX engineers suggested the UEMR originated from the propulsion/avionics system of the satellites as they were orbit-raising at the time of detection."
rickdeckard
> avoid transmitting while they're in the boresight and in general don't transmit toward the antenna
Not sure this will help against the mentioned unintentional electromagnetic radiation (UEMR) likely caused by the electronics of the satellites themselves.
"This radio emission at lower frequencies from Starlink isn’t their downlink frequency, but instead unintentional electromagnetic radiation (UEMR), thought to be caused by the onboard electronics of the satellite."
aragilar
Uh, given there's been radio telescopes there for longer than starlink has existed, I'm not sure why they haven't stopped broadcasting in that area then.
mlindner
It's possible they haven't requested it yet. I've only heard SKA complaining loudly in the media while American radio telescopes have very obvious blackouts visible on SpaceX's map because they've requested them.
null
mentalgear
[flagged]
When an individual transmits on a band they shouldn't the FCC issues a fine. When a company transmits on a band they shouldn't the FCC gives them the band.
https://www.pcmag.com/news/despite-spacex-protests-fcc-clear...
Comment period ended in July.
https://www.fcc.gov/ecfs/search/search-filings/results?q=(pr...