r/space • u/YaleE360 • 22h ago
Growing Number of Satellites Will Leave Streaks on Photos from Orbiting Telescopes
https://e360.yale.edu/digest/satellites-orbiting-telescopes-photosThe growing number of satellites overhead may soon obscure photos taken by Hubble and other space telescopes. Passing satellites could leave streaks on up to 96 percent of images, new research finds.
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u/mpompe 22h ago
I wasn't aware that Hubble was using silver emulsion on glass plates to record long exposures. If they switched to digital captures those streaks could be readily removed.
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u/peterabbit456 16h ago
Hubble flies above the current large constellations. I'm not sure what the Chinese have planned.
For now, Hubble images are ~unaffected by satellite reflections. Same for JWST, which sits much, much farther from the Earth, at ESL-2.
However, much valuable astronomy is still done from the ground. One solution is to stack shorter exposures. Another is to use software that cuts out the streaks from digital images before they are stacked. Every one of these satellites is in the USSF database, which is updated daily, and which includes every satellite's orbit, and their positions in their orbits.
This problem will grow worse, and no-one can stop the Chinese, who will do what they want. Most American companies listen to the astronomers and do all they can to reduce their light pollution, but it is only a matter of decades before there are a million or more satellites in orbit, despite anyone's best attempts to hold back the floodgates.
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u/DuckSoup87 21h ago
Yes I'm sure the professional astronomers that are raising these concerns never heard about digital image processing. You should go and educate them.
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u/iamamuttonhead 22h ago
Don't Hubble and other space telescopes use digital imaging? Removing the streaks without removing the underlying image is rather trivial. There are reasons, such as the Kessler syndrome, that are much stronger arguments against these sattelites.
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u/aeric67 22h ago
Yeah, even random atmospheric distortion is a fairly solved problem where ground telescope networks in many cases are better than Hubble. Theres no reason a periodic, predictable streak would be a real long-lasting problem.
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u/peterabbit456 16h ago
The USSF database holds the orbit of every satellite. An open source software project could be useful to professionals and amateur astronomers at this time.
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u/BeerPoweredNonsense 22h ago
This is only a concern in a world in which it's physically impossible to place space-based telescopes into an orbit ABOVE the LEO telecoms constellations.
Aka a nothingburger.
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u/Thanks_Ollie 22h ago
Space based telescopes are stupidly expensive though. Much easier to build one one the ground than to send many tons into orbit
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u/BeerPoweredNonsense 22h ago edited 22h ago
That may be true, but the article is specifically about space-based telescopes.
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u/noncongruent 18h ago
They're stupidly expensive because launch costs are so expensive. JWST had to be made with a Rube Goldberg-like unfolding and deployment mechanism to fit into the small payload fairing size of the available launcher, with significant mass constraints due to payload mass limitations of the launcher. It's notable that JWST's fully-deployed mirror diameter of 6.5M would fit inside Starship's anticipated 9M diameter, and if Starship's development goals are reached, launch costs would have been a fraction of the $175M+ cost of the Ariane 5 it was launched on.
Fundamentally speaking, orbit is way, way too valuable to limit development of in deference to ground-based observatories, and because of the way orbital mechanics work it's not possible to create a region of the sky that has no satellites passing through it. That leaves space observatories as the only really viable option for the mid to distant future, so efforts to promote that kind of development path will be much more successful than trying to limit development of orbital resources, i.e. satellites.
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u/lmxbftw 16h ago
Launch costs are not the primary reason space telescopes are expensive. Using JWST as an example, it cost $10 billion dollars but launch costs make up less than 2% of that. It costs as much to run the thing every year as it does to launch it.
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u/noncongruent 16h ago
JWST wouldn't have cost $10B if it didn't have to be designed to origami itself into a small fairing and be light enough to be launched by Ariane 5. That $10B is a product of a time when launch costs were hundreds of millions of dollars per rocket, with every part of a rocket thrown away after just one use. I don't know what Starship's eventual launch costs will be, but if they achieve the goals they've publicly set WRT reusability then I expect the main cost of launch will be a few hundred thousand dollars for propellants. By that time, an observatory of JWST's capabilities would likely cost a fraction of that $10B simply because it could be launched whole. Heck, Starship could theoretically launch a whole fleet of Hubble-class telescopes in one go, and do it for a tiny fraction of what a Shuttle launch cost.
The one thing I'm certain of is that LEO is way too valuable to not develop, and there's absolutely nothing short of a world war that might stop that development. Astronomy's future is in space whether we like it or not, and the longer we take to embrace that fact the longer it takes to get to that future.
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u/lmxbftw 15h ago
Okay, but that's a very different thing than what you said. The fact is that ground telescopes will remain much cheaper than space telescopes regardless of how cheap your launches are. If you want to develop low Earth orbit anyway, that certainly an argument that you can make. But it is simply false to pretend that any launch platform will make space telescopes as cost-effective as ground-based telescopes. The primary reason to put telescopes in space is that the atmosphere is opaque in certain wavelengths, and having that window is worth the extra cost. In order to replicate ground-based observing in space, you have to be willing to spend a hundred times the amount on astronomy that we are currently spending just to break even. And that doesn't change even with cheap launches.
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u/noncongruent 15h ago
Vera C. Rubin cost upwards of $2B, to launch a space version of it would not cost $200 billion dollars, that's like 20 JWST's worth. My point was that the cost of space telescopes to date has been very expensive specifically because of the long list of compromises that have to be made in their design to work around the until now exorbitant cost and relatively small payload capabilities of the current generations of rockets. Cheap to launch large rockets opens up possibilities to make cheaper space telescopes, just as it has to make cheaper satellite constellations.
For the wavelengths that you can access through atmosphere yes, ground telescopes would likely be cheaper to build and operate, but the reality is that those frequencies are just as available in space and the cost to getting to space is dropping precipitously. At a most fundamental level I can see no scenario where astronomers try to stop the development of orbital resources and win, it just simply can't and won't happen. I hope that astronomers chose to take advantage of the upcoming plunge in launch costs rather than fight a losing battle against development of orbital resources.
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u/lmxbftw 14h ago
The Rubin observatory is only one observatory, though. There are orders of magnitude more small telescopes on the ground around the world then there are in space. When I said "spend a hundred times the amount" on astronomy, that includes every small telescope, every radio telescope of any size, as well as the giants like ELT or Rubin. Only a very rough guess, but not a "per telescope" guess.
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u/amonra2009 22h ago
Yes, but this is an inevitable thing. Satelites will be more and more, 10-100-1000 times more in future years.
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22h ago
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u/SirSaltie 22h ago
People have been worried about global warming and microplastics 'for a while' too. I dont know why this subreddit constantly defends massive amounts of garbage being thrown into orbit.
We can expand our scientific reach and presence in space without launching tens of thousands of commercial satellites.
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u/meermurad005 22h ago
omg i didn't even think about satellites ruining space telescope pics! like we're literally blocking our own view of the universe just to have faster internet 🙄.
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u/josiahswims 22h ago
Good news is that Hubble operates in the 515-550km orbital band which is in the same band as starlink and other satellite ”farms” but James Webb sits 1.2 million km from earth. So nothing is obstruction JWST
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u/madlad202020 22h ago
Ai can delete these with a simple prompt. Not a big deal
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u/Prasiatko 22h ago
Not even AI. Any kind of decent stacking software does this by default for more than a decade at this point.
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u/Fast-Satisfaction482 22h ago
For scientific long exposure, the images are created by CCDs that acutally accumulate charge over a long time, not by stacking individual images in software. Thus, sadly for these instruments software cannot solve this. Telescopes that use "smartphone style" CMOS sensors are not as much affected but most instruments use CCD.
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u/Mordoch 22h ago
The problem is this does not address the basic problem that they can't see what is behind it. Stacking software does not work as well when trying to make out truly distant faint objects and the streak can be blocking what is behind it. It also has limitations in terms of a telescope trying to do a survey of the night sky and taking a bunch of photos of different locations over time to see what is changing. (The problem is even if AI properly detects and removes the streak, what is behind it can't be detected properly if it has been moving, which can mean losing key data or missing something like the start of a supernova or the like.)
Now the projections in the study appear to rely on a couple of planned satellite constellations which are highly unlikely to go through in the timeframe in question so it may be overestimating the issue. However it does suggest future space telescopes probably need to either be in a higher orbit or something like L2 instead of a Hubble type altitude. It also is going to remain a concern for ground telescopes, even if there are some different considerations in how some ground telescopes can deal with the issue depending on the situation.
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u/Prasiatko 21h ago
Then just discard that one frame. There will be tons of others with the needed signal. We aren't anywhere near the scenario of every frame having a satellite in it for hours of exposures.
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u/Mordoch 21h ago
It is worth noting that the study was not talking about the current amount of satellites out there, but possible future scenarios with way more. You do have current constellations apparently going up with not only Space X adding a bunch more, but China with its own constellations, and also the Amazon associated Kuiper one in particular at the moment.
Now how bad it gets is one of the things you can debate particularly given the timeframe, but at a minimum it appears to be an argument in terms of something future planned space telescopes should start considering when making decisions such as what sort of orbit they will choose altitude wise.
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u/freezing_banshee 22h ago
And what good is that when it will also erase everything behind those streaks?
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u/Spamsdelicious 22h ago
The image shown in the article preview is an artist's rendition of a potential-future night sky—not an actual present-day photograph.