Listen: https://soundcloud.com/astrophiz/astrophiz225-dylangrigg
Transcript below …
satellite intrference, radio astronomy, radio telescopes, elon musk,Unintended Electromagnetic Radiation (UEMR), Radio Frequency Interference (RFI), Satellite Constellation Interference, Square Kilometer Array (SKA), Radio Astronomy Pollution, Low Earth Orbit (LEO) Satellites
Summary: In this episode of the Astrophiz podcast, Dr. Dylan Grigg, a High-Performance Computing specialist and astrophysicist, discusses his groundbreaking research on unintended electromagnetic radiation (UEMR) from satellite constellations. Using the Engineering Development Array 2—a prototype for the Square Kilometre Array (SKA) in Western Australia—Grigg conducted the world’s largest survey of low-frequency satellite emissions, analyzing 76 million images of the sky.
He reveals that tens of thousands of Low Earth Orbit (LEO) satellites, particularly Starlink, are “leaking” radio frequencies. Unlike intentional communication signals, this unintended radiation originates from onboard electronics and often falls within protected frequency bands reserved for radio astronomy. These “noisy” satellites threaten to drown out the incredibly faint signals from the early universe, such as those from the Epoch of Reionization. Dr Grigg emphasizes that while intentional transmissions are internationally regulated, current policies do not yet cover UEMR, highlighting an urgent need for updated global spectrum management to protect the future of deep-space observation.
Transcript:
Brendan: Welcome to the Astrophiz Podcasts. My name is Brendan O ‘Brien and we’d like to acknowledge Australia’s first astronomers, the Aboriginal and Torres Strait Island people, the traditional owners and custodians of the land we are on.
This episode is produced on Yorta Yorta and Pangarang Country in the East and Whadjuk Nyoongar country in Perth.
… and we’re also asking you to influence your local politicians with a message that we really need to change our energy policies and move to renewable energy sources to mitigate the effects of climate change.
Each month, We love bringing you two fabulous episodes … on the first of each month, our friend, molecular pharmacologist, toxicologist, and amateur astronomer, Dr. Ian “AstroBlog” Musgrave, brings you his monthly SkyGuide with all the essential observational highlights for telescopers, astrophotographers and naked eye observers.
Then, later each month, we bring you an exclusive and in-depth interview with a noted astrophysicist, astronomer, particle physicist, radio telescope engineer, data scientist or space scientist.
And we discover their science journey and rare insights into how they think, when they think best, and how they conduct their amazing research into exactly how our universe works.
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Today’s episode features Dylan Grigg, a fabulous PhD from Perth in Western Australia.
EDIT: Dylan has just been awarded his PhD ! Congrats Dylan!
Dylan has been doing amazing work that impacts on the effectiveness of every radio telescope and array on the planet.
He has revealed the presence of unintended radio frequencies leaking from the tens of thousands of low -earth orbit satellites above us. And these leaking frequencies have the potential to drown out the very faintest of frequencies that tell us what was happening at the very dawn of time.
Let’s zoom over to Perth.
Brendan: Hello, Dylan.
Dylan: G’day, Brendan. How’s it going?
Brendan: Yeah, very good. Great to be speaking with you. Now, today, listeners, we’re really lucky to be speaking with Dylan Grieg, who is a high-performance computing specialist who has been doing groundbreaking work with the prototype of the world’s newest, biggest and most expensive radio telescope ever built … the SKA … the Square Kilometer Array. His work is shaping the way the world’s astrophysicists will use the huge amounts of data collected from the SKA to extract meaningful new understandings of the origins and evolution of our universe …
and thanks for speaking with us today, Dylan.
Dylan: Thanks so much for having me on.
Brendan: It’s a pleasure, okay. Now, before we talk about your current work at DUG and Curtin University in Perth, Western Australia, can you tell us where you grew up, please, Dylan? And could you tell us how you first became interested, or in your case, obsessed … with science and space?
Dylan: Yeah, sure. So, yeah, growing up all my whole life in Perth Western Australia … and I think the first time I got introduced to space and all the interesting things up there was from my old man … I remember reading some books about black holes when I was younger, and I found it quite interesting, just purely from an interest point of view …
I guess I kind of followed that interest a bit through school, and then I got a bit more interested in science, and then kind of led to where I am today, I guess.
Brendan:Fantastic. So, after that successful school career, you were awarded your Bachelor of Science degree in Physics at the University of Western Australia, then your Masters.
Then you moved over to Curtin University to complete your PhD in astronomy and astrophysics. Now, I believe you’ve already just submitted your thesis and you’re eagerly awaiting the response from the examiners. Is that correct?
Dylan: Yeah, so the examiners have gotten back now and made a couple of small changes and so I’m just purely waiting on the university to get back to me now.
Brendan: Excellent. I’m really looking forward to calling you Dr. Dylan Grigg, but let’s hold back on that until you’ve got the actual paper in your hand and the floppy hat.
So first up, congratulations on getting your thesis handed in. And look, we do understand what a huge undertaking challenge and achievement this is.
Now, secondly, for our early career researchers and young astrophysicist listening, could you tell us how you arranged that transition from undergraduate to PhD student and why you made the decision to embark on such a challenging PhD journey at Curtin?
Dylan: Yeah, sure. So, yeah, thanks for that. So, yeah, I finished my undergrad in physics and conservation biology and I knew I wanted to follow through with something astronomy like. So I had to talk to one of the lecturers who lectured me and he ended up … he wouldn’t want to know this … but he ended up convincing me out of it in the end.
So I managed to get a job as a geophysicist and still at the same company now eight years later. But during that time, I had an opportunity to work with some of the researchers at Curtin, some of the astronomers, and I got offered a PhD position from one of them.
And so, yeah, I took it. So I actually went straight from my undergrad, enrolled as a Master’s, and then changed it to a PhD in the end.
So I managed to skip the whole Master’s part of it.
Brendan:What a great strategy to supercharge your Masters and turn it into a PhD. OK, now, we know how important it is to have supportive supervisors and mentors.
Now, we did interview your brilliant PhD supervisor, Professor Steven Tingay, way back in 2018.
Would you like to tell us about some of those people who’ve inspired and supported you as a scientist and as a PhD researcher?
Dylan: Yeah, so Steven has been a huge source of support for me.
He was the one who offered me the PhD position, so without him, I wouldn’t even be in this position now. Yeah, he’s really pushed me to explore different ways of research and different methodologies, which I wouldn’t have done before. And really, this PhD now has increased my drive and passion for science and doing research. And, yeah, I can’t think of doing anything else now.
I also had a high school physics teacher who kind of was the reason that I followed through with physics for my undergrad at uni. So probably those two people have had the biggest impact on me science -wise.
Brendan: Thank you. All credit to Steven Tingay and a science teacher. We love supporting science teachers. Awesome!
Now, the fourfold plan for today is to have a brief look at your PhD, find out about the frequencies that are being transmitted by orbiting Comms and Internet satellites, both intentionally and accidentally, then look at your work on identifying the unintended electromagnetic radiation that’s leaking from huge constellations of satellites like StarLink, which are impacting on research because you’re using extremely sensitive radio telescope arrays.
How does that sound as a plan, Dylan?
Dylan: Yeah, sounds good.
Brendan: Okay, so first up then, can we have a quick look at your PhD thesis to help us understand your personal research trajectory for … I’d know at least the last three or four years.
Your thesis title is: “Characterization of the prevalence of radio frequency emission from satellites at SKA low frequencies with SKA-Low prototype stations”.
Now, what big questions were you asking and what problems did you have to work through and overcome for your thesis?
SKA-Low Frequencies: 50 to 350 Megahertz.
Dylan: Yeah, sure. So for the low frequency half of the Square Kilometre Array that’s being built here in Western Australia, it looks over a very specific frequency range and that frequency range is 50 to 350 Megahertz. And within that frequency range, it wasn’t well known which satellites specifically would be visible at those frequencies to know if they would affect data that was captured by the SKA when it gets up and running … and also by other radio telescopes around the world that also look at those frequencies.
It was known that a lot of them were getting detected, but a more systematic study of it needed to be done.
So that was kind of the drive for my PhD research. And so in that time, in the last three years, the literature’s come quite a long way. And I guess the biggest result from my PhD research was I captured a lot of data with this telescope that I’ve used called the Engineering Development Array 2.
Dylan captures 76 million images and found a majority of Starlink satellites in the protected frequency bands
And so I took 76 million images of the sky. Each of these images was two seconds of what the sky looked like in that two seconds. And then I pretty much just searched through all of those images for satellites. I had to build up all my own algorithms to do that.
And the result of that was that we found, well … a lot of satellites. The majority of them were StarLink satellites and so I was able to report the number of satellites and the frequency both the actual frequency and how often in time they were detected are for each of those frequencies so to give astronomers an idea of whether or not they’re likely to see satellites if they’re reporting data at those frequencies.
And some of those are protected frequencies for radio astronomy. And we still detected some of these satellites in those protected frequency bands. And so post -PHD now, I’ve been working on trying to translate my research so it can be used for regulation in the future.
Brendan: Yep, and that’s a very long road, and we may get to talk about that a bit later. So
that brings us up to date with your thesis. Now, did you and your family celebrate when you handed it in?
Dylan: Not yet. I’m waiting to hear back from the uni first, and then I’ll let out my sigh of relief.
Brendan: Oh, such disciplined, Dylan. Okay, thank you.
Next, can you tell us a little bit more about the frequencies that are being transmitted by those orbiting comms and internet satellites, both intentionally and accidentally …
You mentioned protected wavelengths?
We understand that the purpose of these satellite constellations is to transmit signals to Earth, and these transmissions are designated downlink frequencies and they’re covered by, as you mentioned, international treaties.
Now, is it true that these intentional frequencies don’t really pose a huge problem for ultra -sensitive radio telescope arrays that you’re constructing the SKA low? Is that correct? And for our propeller heads, what actual frequencies are we talking about here?
Dylan: Yeah, sure. So ideally from an astronomer’s point of view, you’d have as much of the spectrum, whether that’s visible, radio, ultraviolet, whatever, as much of that as possible, without any terrestrial transmission in between so that you could look across that whole electromagnetic spectrum.
But of course, astronomers have to coexist with private industry. So for all the radio communications on Earth or in space. So yeah, we have to coexist together. And so that means that there’s parts of the radio spectrum which are allocated for private industry.
Commercial satellites are allowed to only transmit at allocated frequencies
“Like in the frequency range for the SKA-Low, there’s bands, which are for satellites for intentional transmissions. And so the satellites are allowed to transmit at these frequencies. And they’re so bright that you can’t do any astronomy at those frequencies. That’s just how it is.
But there are specific frequency allocations for radio astronomy. It’s quite small. I think it’s 6 % of the range of frequencies that the SKA looks over are protected, but we also try and do observations in the frequencies that aren’t protected as well.”
Dylan discovers a new type of emission from satellites
“So anyway, yeah, so we detected a lot of satellites transmitting at the designated downlink frequencies like we would expect … but we also found a new type of emission from satellites … where there’s some emission coming from the satellites but it’s not intentionally transmitted so it’s somewhere on board the electronics which we’re quite not sure what part that is at the moment and it’s equivalently as bright as the brightest radio sources in the sky, astrophysical sources of radio emission.
So they’re still bright and they have a very large bandwidth, which means that they’re visible over almost all the frequency bands that we look at over this SKA-Low frequency range. So what I was trying to do was understand what the frequency of them was and, yeah, how widespread this emission actually is.”
Brendan: Okay, look, to summarise to this point, you’ve got some amazing results. I think it’d be fair to say that those results scared the bejesus out of some of the people in the radio astronomy community. So you discovered radio emissions leaking from satellites across a broad range of frequencies. What has been the reaction to the publication of your research findings?
Dylan: Yeah, so we put out some first results on it a couple of years ago, and then the big survey that I did in the PhD thesis got published this year.
Obviously, it’s a cause of concern because you don’t want to be seeing these satellites when you’re looking for extremely faint signals from the early universe or from other astrophysical sources.
But in a way … we kind of put this research out to hope that we could introduce mitigations somehow. So we increase awareness of it at first by putting the paper out. And now we’re hoping to double down on that by talking to the right people to introduce mitigations for it.
And there’s a few different ways of doing that. You can introduce regulatory measures or astronomers have to introduce their own, whether that might just be loss of data in some cases or coming up with clever algorithms to be able to filter it out of the data.
Brendan: Okay. While we’re talking about mitigation then, this problem has a potential to impact on every radio telescope we have, but also, as you mentioned, it’s all about finding solutions.
Now, you’ve already solved the problem of electromagnetic radiation leaking out from your labs and workshops out in the field, out at the Murchison site by putting those labs inside huge double Faraday cages. So you’ve also applied filters to remove some rogue and predictable frequencies that can corrupt your data stream.
Could we just use metallic paint to paint a Faraday grid on the walls of each satellite before? LOL, probably not. Stupid idea. Look, there’s no silver bullet ever is there?
So is SpaceX working to identify the onboard components that are, I’m assuming they’re aware of this problem, are they working to identify the components that are actually leaking the electromagnetic radiation?
And what do you currently think about the possible solutions for this mitigation problem that we have?
Dylan: Yeah, sure. So interesting idea. Like for optical astronomy, so yeah, the wavelengths that our eyes see, SpaceX actually have painted their satellites with a different kind of paint that was supposed to decrease how bright they were from the air. Something like a Faraday cage around the satellites would mean that they’re not able to communicate with the air. But going on the right track, it makes it hard when we don’t know exactly what part of the satellites this emission isn’t coming from.
And in particular, I’ll just say the vast majority of the satellites that we detected with this leaking electromagnetic radiation were StarLink satellites. We have talked to SpaceX about it, so they know the problems there for us astronomers.
But at the end of the day, they’re a private company and what goes on inside their company, the public or other researchers aren’t always privy to. So I’m not sure if they know exactly what components coming from yet or how much they’re working on it. But we just hope that each time we come out with new results or other people around the world come out with new results that it gets shared to them.
And they’ve made good mitigations for optical astronomy in the past. So we hope that something similar can be done for the radio part of the spectrum in the future as well.
Brendan: Beautiful. Thanks, Dylan. Optimism and great science do go hand in hand.
Now, as we’ve just seen, we know that science doesn’t always sail smoothly, and we’re really happy now to put our propeller heads back on again for a short time. Would you like to share with us some details of a particular part of your research that you’re working on right now that’s driving you crazy or is astonishingly exciting? Well, perhaps it’s even both?
What’s going on, Dylan?
Dylan: “Yeah, well, I guess like I mentioned, the natural progression of this work goes from the data science of capturing the data, analyzing it, getting the signals out, and then getting quantitative results out, and then presenting that in the papers like we have, which are most accessible to astronomers and now the yeah the progression on from that is also making it that it’s translatable for the regulation people … which work for example with different units and against different standards and so that’s a little bit different to the PhD work
…it’s going more into yeah understanding very complex regulatory frameworks.
And so, yeah, we’ve been in contact with some people who are helping us with that. So hopefully we’re able to, yeah, translate our past results and other people’s past results into something which could be enforced as regulation in the future, because the unintended electromagnetic radiation actually falls in a bit of a grey zone at the moment, outside of regulation.”
SpaceX is doing nothing wrong with their satellites at the moment
“So, like, for example, SpaceX is doing nothing wrong with their satellites at the moment. But what we’re hoping is that regulation can get introduced so that the unintended electromagnetic radiation can be regulated in the future so that it’s less of an impact for astronomy, especially over those protected frequencies as well.”
Brendan: Cool. Fingers crossed, Dylan, with regards to your work at DUG or on the SKA, you are deeply immersed in data wrangling some of the most complex and puzzling phenomena in our universe. Now, how do you do your best thinking?
What circumstances do you usually need to swim clearly through that sea of data and come up with verifiable conclusions. What situations and surroundings support your best thinking, Dylan?
Dylan: Yes, a good question. I mean, there were plenty of times during the PhD, especially in the last year where it got really hard. Like, I’d have a problem and I’m just banging my head against the desk for a week or weeks even and can’t seem to be making any progress. So it’s quite hard to push through when that does happen.
But I find that it’s easier said than done, but sometimes taking a step back and reassessing what I’m actually trying to get out of my work helped me a lot.
I also found that my best thinking was done away from my desk and away from the computer, like if I’d be out just having a walk or I don’t know in the shower just mulling things over sometimes that’s where I did my best thinking … and yeah, most of the time those breakthroughs that I had with my research or pushing through those hard parts weren’t at the desk … so yeah, that was a valuable skill that I learnt during my research.
Brendan: Excellent! Thanks Dylan … Now, I’ve had a look at some of your ArXiv papers on the ArXiv server, and I noticed you wrote a number of them when the impact of the COVID pandemic was still evident back in 2022.
How did COVID affect you and your family, and what was the impact on your studies and your astrophysics research? Were there any lessons learnt?
Dylan: Yeah, good question. To be honest, me personally, COVID didn’t really affect my research output that much. We had a lot of lockdowns here in Perth, well, as a lot of places in Australia did.
But yeah, from the research point of view, I was still able to collaborate with people online when I needed to. So, Yeah, in terms of research, didn’t really affect me too much. And I know it was very different for a lot of other people. So I guess I was pretty lucky with that.
But I guess it really made everyone comfortable with being able to communicate online over Zoom calls or over emails more frequently. And I think it’s also given people a good balance with being able to work from home in the future as well.
Brendan: Yeah, cool. Okay. Can you tell us about some of the things outside your DUG work and your PhD -type research that regularly brings you great joy?
Dylan: Well, I can say for sure that the thing that kept me sane through all the research was exercising regularly. I do a lot of running and I play footy as well. And definitely that kept me sane and gave me an output sometimes for when I got really frustrated with uni and couldn’t make any progress or anything.
And, you know, I’d be able to come back at the end of the day after doing some exercise with a fresh mind. And a lot of times that really helped me.
Brendan: Excellent. Fantastic. Thank you. Now, you’ve done presentations of your work, both locally and internationally, I saw earlier in the year you’re over in Europe giving a presentation. I’ve listened to a couple of your radio interviews that you’ve done recently. Is outreach an important part of being an astrophysicist?
Dylan: Yeah, most definitely, and it’s definitely something that is pretty new to me.
The speaking at the national conferences was quite daunting as somebody newer to the field. So plenty of practice was required for sure for that.
But I’ve definitely improved my skills over the course of the PhD. But yeah, being able to communicate very technical result to both technical people and a layperson audience can be quite difficult and it’s something that I’m trying to get better at. But it’s very important that the researchers do communicate their scientific output because they know the work better than anyone else. And so them being able to communicate it effectively is very important so that future researchers can understand the implications. And so also the general public can understand them if it has more of an effect on everyday life, which for astronomy not often does … It doesn’t often.
Brendan: Exactly. Thank you. Okay, well, now the microphone is all yours, and you’ve got the opportunity to give us your favourite rant or rave about one of the challenges that we face in science in equity or representations of diversity in science denialism, that’s my favourite bugbear, or science career paths, or your own passion for research that you mentioned earlier, or just our human quest for new knowledge. The microphone is all yours, Dylan.
Dylan: Thanks. Yeah, I’m definitely very grateful that we have a very welcoming environment at Curtin University for anyone who wanted to study astronomy. Especially compared to some other parts in the world, I feel very grateful to have done it in Australia.
And I guess from the scientific side, I didn’t really appreciate the breadth of radio astronomy before I started doing the PhD and it’s really interesting because radio waves don’t get absorbed by the universe as much as other shorter wavelengths.
So it allows astronomers to probe right into the early universe and I think some of the questions that radio astronomy is trying to answer like how the universe looked closer to the Big Bang and other really exotic phenomena which we see in deep space is really interesting … and yeah I hope that in the future I’m able to stay connected to radio astronomy and contribute to the field as well because i just find it really interesting.
Brendan: Excellent and I also notice that the ARC Discovery Grants are coming out as we speak. So we hope those young radio astronomers in Australia being fortunate with those grants. Thank you, Dylan. Now, is there anything else that we should watch out for in the near future? What are you keeping your eyes on?
Dylan: Yeah, well, definitely keeping my eye on the SKA as it gets up and running, both the SKA-Low and the SKA-Mid. There should hopefully be some really cool results that come out of it, like one of the big science cases for the SKA is looking at the Epoch of Reionization … so looking at what the early universe looks like.
And also the quickly developing field of long period radio transients and Fast Radio Bursts is also very interesting, so I’m keen to see where that goes.
Brendan: Indeed! Look, I share that FRB challenge too … knowing what’s going on with them it’s a lovely ongoing puzzle with a few hot candidates but we still haven’t nailed it …
Well thank you very much … almost Dr … Dylan Grigg … On behalf of all of our listeners, and especially from me, it’s been really great to be speaking with you all the way over there on the western half of Australia and I’m looking forward to … first of all … hearing the result of your PhD. That will be a huge celebration for you and your family and it’s great to know that you’re there teaming up with others to solve some of the most important problems in radio astronomy.
Thank you especially for your time in that incredible schedule that you’ve got and the pressures to analyse all that data and make sense of it. And good luck with all your next adventures and all of those future travels. I hope they’re all wonderful.
And may your career continue to be out of this world! Thanks, Dylan!
Dylan: Thanks so much, Brendan. It’s been great talking to you. Thanks for having me on.
Brendan: Bye.
Dylan: See ya.
SFX: Morse Code snippet
Brendan: And remember, Astrophiz is free, no ads, and unsponsored.
But we always recommend that you check out Dr. Ian Musgraves’ Astroblogger website to find out what’s up in the night sky.
Heads up. Astrophiz always takes a festive season holiday break over December and January. But before we take this break, we’ll be bringing you a fabulous interview with a wonderful Irish solar physicist, Dr. Laura Hayes, coming very soon. Stay tuned. Keep looking up.
SFX OUTRO: “Radio Waves”
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