Vera C. Rubin Observatory/LSST
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This is a nice writeup about Rubin/LSST, with some quotes from a colleague about the satellite problem:
www.optica-opn.org
Optics & Photonics News - The Vera C. Rubin Observatory
A specially designed, ultrafast telescope and the world’s largest CCD camera could expand our understanding of the universe—if a fog of telecommunications satellites doesn’t spoil the view.
www.optica-opn.org
Although I think technically I'm not supposed to say too much about the details, a current annoyance (LSST will be very good at spotting satellites) on the project is featured in this article about "sensitive topics" research. This is the other half of the "there are too many satellites" problem: the ones that don't want to be seen in the first place.
Well, I've got a bit of news for the "don't want to be seen" satellite crowd... if you're standing in the room, unless you genuinely can become invisible, you're going to be seen. Demanding that everyone with eyes not look in your direction doesn't work too well, as everyone now knows that there's SOMETHING in that direction that doesn't want to be seen or known about.
Reality has an automatic Streisand Effect going on.
Reality has an automatic Streisand Effect going on.
Eh, I think there is a decent gap between the US government asking the observatories it directly funds not to share certain images; and suggesting that the USA is demanding that no-one look in certain directions. The former is at least within spitting distance of reasonable; the latter is entirely laughable. People have been publishing ephemera tables and photographs of NRO satellites for decades, so it seems implausible that anyone would expect anyone to take the latter suggestion seriously.
Everybody (that cares to and that the NRO would care about knowing) knows where NRO's satellites are, because they're too big to be concealed and when you rule out everybody that is more than happy to tell you all about their satellites you're only left with intelligence birds.
What really matters though isn't that they're up there. It's what they're looking at and what they can see.
What really matters though isn't that they're up there. It's what they're looking at and what they can see.
It's been tried a few times before, and the result of any kind of removal of satellites from public databases is that amateurs find them again (because satellites are really, really, really bright) and put them in another database.
I would imagine that if amateurs can find them its just confirming that Russia/China almost certainly have already
moosemaimer
Ars Scholae Palatinae
Trying to hide something's orbital parameters seems like a good way to ensure someone else puts something into an orbit that intersects without knowing.
Is the request to hide orbital parameters, or is it to censor the high quality images captured by one of the largest telescopes in the world?
It's not really possible to hide a satellite's orbital parameters unless it's literally completely quiet. Because it HAS to be moving at a very significant speed, even crappy SDRs are able to track the doppler shift of any signal that a satellite is putting out. And in case you're wondering 'but what if the signal is really really low?' - yeah, amateurs have been able to listen to the attowatt-level signals from Voyager. No matter how well you try to beamform and shield your signal, it requires nothing more than $200 worth of radio equipment and the free software Audacity to figure out the orbital parameters of an unknown satellite.
It might be plausible for this aspect of observability to change with radio communications replaced by optical communications, especially to relay satellites rather than to the ground. For all we know, this is the actual purpose of the Starshield project, and the broader secure communications stuff that's justifying the expenditure publicly is just a cover.
So, some clarifications: this is somewhat similar, but not quite as bad, as the restrictions that were put on Pan-STARRS early in their survey. Those restrictions were lifted after a few years.
We have a tech note describing the details. The main parts are an 80 hour release delay (previously full images from one night would become public the next morning) and not sending alerts on anything that could be a satellite. We didn't want to alert on satellites anyway (they're not a science goal, so they're just junk in the data stream), but there's the usual 80/20 problem of getting "everything" instead of just best effort. Plus, very near earth asteroids (the ones most likely to be dangerous and one of our top survey goals) can move fast enough to look the same as a satellite streak. "Oops, we missed that city killer because we can't alert on streaks" is not a good look, but we're stuck with it.
There is already a secret table of the orbital elements of recon satellites; I think it's held by Space Force now? That is consulted when checking for "dangerous" passes of commercial satellites, without ever releasing the list of secret ones. Similarly, when they say "don't release alerts on anything in these orbits", that list includes real things, non-secret satellites, and empty sky.
The thing that makes this so ridiculous to me is that amateur satellite hunters already do a pretty good job tracking supposedly hidden satellites with mostly binoculars and small telescopes. The Chinese and Iranian intelligence agencies would be absolute idiots (they're not!) to not know where all our stuff is with only slightly more sophisticated gear.
We have a tech note describing the details. The main parts are an 80 hour release delay (previously full images from one night would become public the next morning) and not sending alerts on anything that could be a satellite. We didn't want to alert on satellites anyway (they're not a science goal, so they're just junk in the data stream), but there's the usual 80/20 problem of getting "everything" instead of just best effort. Plus, very near earth asteroids (the ones most likely to be dangerous and one of our top survey goals) can move fast enough to look the same as a satellite streak. "Oops, we missed that city killer because we can't alert on streaks" is not a good look, but we're stuck with it.
There is already a secret table of the orbital elements of recon satellites; I think it's held by Space Force now? That is consulted when checking for "dangerous" passes of commercial satellites, without ever releasing the list of secret ones. Similarly, when they say "don't release alerts on anything in these orbits", that list includes real things, non-secret satellites, and empty sky.
The thing that makes this so ridiculous to me is that amateur satellite hunters already do a pretty good job tracking supposedly hidden satellites with mostly binoculars and small telescopes. The Chinese and Iranian intelligence agencies would be absolute idiots (they're not!) to not know where all our stuff is with only slightly more sophisticated gear.
Even all the 'optical' comms (from mmWave to THz to true optical) diffract and diverge enough to be easily detectable. Even the best modern optical beam devices still have like half a degree of divergence to 10% intensity.
It's an unwinnable physics puzzle - to get enough SNR for anywhere near useful amounts of communication you need to have fairly significant comms power, and once you have that you're spreading around so many photons that it becomes very easy to see stuff with even mundane electronics. Like, a DSLR sensor can detect single photons these days.
This is separate from the threat posed by possible military devices in space. You can know exactly how they move, but that won't tell you what they have inside or when they might deploy a deadly payload.
Close to where all the big observatories are is a small, very touristy town called San Pedro de Atacama. There lives a young French baker, who fell in love with a local and stayed, and promptly opened a genuine, no-holds-barred fantastic French bakery right there. I’ve been to it.
He called it "Franchutería" as "Franchute" is slang for "French guy." I guess a decent translation would be "The Frenchierie.”
It is therefore entirely possible not just to find a croissant, but a GOOD croissant, and a very genuine baguette, in the area.
Also, if gotten at the observatory itself, it’d probably be Nescafé, which (still, alas) is the default “coffee” in Chile. Even restaurants will serve you Nescafé unless you specifically ask for -and they have the equipment to make- espresso. Coffee shops are legit, but restaurants are a crapshoot.
—Chilean guy
The main optical observatories are mostly quite a bit further south, closer to La Serena than Antofagasta. But it's good to hear that there's a good bakery! I mostly wasn't impressed with the bread on my trips to Chile. The ice cream and empanadas though, those were top.
Yeah, all the coffee snobs I know who have gone down had a bit of a rude awakening because of this.
My memory is that the coffee at Paranal Observatory is pretty decent -- at least espresso and its variants, because Paranal is operated by the European Southern Observatory, and there are a lot of Italian astronomers, and they (at least) weren't going to put up with Nescafé.
Plus, the observatory Residencia was the "hotel" featured in the last act of the James Bond film Quantum of Solace. (Though the real rooms aren't as nice as the ones in the movie.)
I don't think LSST will cause any actual security issues. I find it hard to believe that china/russia are not successfully tracking all of our spy sats already.
Whether or not that's true (and for the record, I agree with you completely), we've been told we have to work extra hard to remove potential satellites.
As I said, it's the 80/20 problem: doing 80% of the work takes 20% of the time, it's the remaining 20% of the work that's really hard (whatever the exact fraction, I hope you get the idea). We've always planned to mask out things that are likely human-made (aka long streaks), but it's a lot harder to catch all of them. This also puts requirements on how we share data (see the details in the tech note I linked above) both internally and externally.
There are also subtle details like what do you do about something that might be a satellite streak that goes off the edge of a detector? It could be a satellite, it could be an asteroid, it could be a very nearby asteroid moving very fast. Those latter are things we really want to catch (its one of our design goals), but there's not much to distinguish between a barely-streaked satellite and a barely-streaked asteroid.