New “Satellite Constellations” Threaten Research, Astronomers Say

Jan 16, 2020

SpaceX launched 60 new Starlink satellites into orbit last week, in their quest to expand Internet access across the globe. The company hopes to have 1500 in orbit by the end of the year, and other companies are planning launches, too. That could mean tens of thousands of new satellites in the sky, which is bad news for astronomers. KNAU’s Melissa Sevigny spoke with Lowell Observatory director Jeff Hall about how these “satellite constellations” threaten astronomical research.

This image taken from a Lowell telescope on May 25, 2019 shows the trails of newly launched Starlink satellites passing across a galaxy group. The satellites diminish in density and brightness when they reach their final orbit altitude.
Credit Victoria Girgis/Lowell Observatory

Melissa Sevigny: Are they brighter than the usual satellite up there?

Jeff Hall: That’s what surprised everybody. They were much brighter than we expected satellites of their configuration to be. I think that surprised SpaceX, too. Everybody was caught off guard at just how bright they are, and of course that’s what sparked all the attention.

So if you’re up at, say, the Discovery Telescope looking at a faint object, a galaxy or nebula, what are the chances that one of these bright satellites is going to streak by and ruin the view?

Well, it depends on how many are up there. Right now the chances are fairly low, although one of our astronomers was observing at one of the facilities in Chile late last year and sure enough, there went three Starlinks right through the image. You can’t easily filter that stuff out or subtract it out—sometimes you hear that—really the bright streaks completely saturate the detector when they streak through and create all kinds of problems in the image. Really, they can render an image useless.

I know astronomers have been speaking with SpaceX about what can be done about this problem. What sort of solutions are available?

This is where I don’t really know what the answer is, because if the satellites are just below visibility to the naked eye, they are incredible photobombs to a telescope like the Lowell Discovery telescope or any of the other major facilities around the world. The amount of dimming that would have to be done to get them down to the point that they’re not impacting some of these cutting edge facilities that we’re building—I don’t see how you do that. It’s going to take creativity and innovation, which is something I think SpaceX prides itself on, so hopefully this will be a good challenge we can mutually address.

SpaceX is testing basically just painting one of the satellites black, right?

Yes, that’s in the current launch, they’re calling it DarkSat, yes. It’s one of the sixty. You know, darkening the satellite, it won’t work as well. If you just paint the whole thing black that’s not operationally viable because of all the thermal problems it would create from the absorbed radiation, it just heats up. So we’ll see how this one does. As this year goes along—it’s pretty clear to me, this is the year we need to get ahead of this and figure this out. 

Can you talk about what it’s important to you to protect astronomy and dark skies?

Astronomy is the study of our own origins. We are this amazing collection of atoms and all these atoms were created out in the universe, in the thermonuclear furnaces of stars, some of them in the Big Bang itself. We are in a way almost children of the universe trying to understand our own origins and answer some of humanity’s oldest questions. That is uplifting, it’s inspiring, it prompts us to be our better selves, I think…. But you know, research and understanding our world benefits us in many different ways and it’s worth preserving.

Jeff Hall, thanks for speaking with me today.

My pleasure.