A New Satellite Can Peer Inside Buildings, Day or Night • Hacker News Board

Re: A New Satellite Can Peer Inside Buildings, Day or Night

#81

Post by baybal2 » Thu, Dec 17, 2020, 6:46 PM UTC

lemonspat wrote: post #11

geomark wrote: post #5

Earlier quoted context omitted.

Also used to track submerged submarines by detecting ocean surface disturbances caused by the underwater wake of the submarine. Same benefits: works at night and through cloud cover.

That is astounding! something I was unaware about before. At what depth could it be measured?

The infamed laser on Tu 142 was said to get to only get to 50m, but that was a "direct imager" which relied on direct reflection, and seventies-eighties era technology.

Newer ones are directly sensing density, and temperature changes in the seawater by sensing Raman shift, and are supposedly much better. No known data in public of course.

Re: A New Satellite Can Peer Inside Buildings, Day or Night

#82

Post by LeifCarrotson » Thu, Dec 17, 2020, 8:04 PM UTC

jolmg wrote: post #80

wlll wrote: post #49

Earlier quoted context omitted.

I think this is a balance. Being the only house in the area that can't be seen into might get you more attention someone being able to see you in your underwear at a 50cm x 50cm resolution.

Unless you live underground, then you'll just look like the rest of the ground. EDIT: On a more general case, I wonder how expensive and feasible it would be to cover the roof/ceiling and walls with an array of 9ghz emitting "pixels" with the wire mesh behind that. Then show the satellites whatever image you want. Make it look like funny stuff is going on inside for their own amusement. Wouldn't be able to account fo…

The satellite is looking at the of flight and intensity of the reflected signal, not 'color'. It's basically monochrome. You can make your ceiling either very massive or very conductive to reduce the signal reflected, or install a corner reflector in the attic to overwhelm the sensor with its own high-intensity signals (like taking a photo in a mirror with the flash on).

Re: A New Satellite Can Peer Inside Buildings, Day or Night

#83

Post by jolmg » Thu, Dec 17, 2020, 8:32 PM UTC

LeifCarrotson wrote: post #82

jolmg wrote: post #80

Earlier quoted context omitted.

Unless you live underground, then you'll just look like the rest of the ground. EDIT: On a more general case, I wonder how expensive and feasible it would be to cover the roof/ceiling and walls with an array of 9ghz emitting "pixels" with the wire mesh behind that. Then show the satellites whatever image you want. Make it look like funny stuff is going on inside for their own amusement. Wouldn't be able to account fo…

The satellite is looking at the of flight and intensity of the reflected signal, not 'color'. It's basically monochrome. You can make your ceiling either very massive or very conductive to reduce the signal reflected, or install a corner reflector in the attic to overwhelm the sensor with its own high-intensity signals (like taking a photo in a mirror with the flash on).

I never said anything about color, though. Monochrome displays also have pixels. Color pixels aren't the only type of pixel.

Re: A New Satellite Can Peer Inside Buildings, Day or Night

#84

Post by SirLuxuryYacht » Thu, Dec 17, 2020, 9:03 PM UTC

grendelt wrote: post #36

lemonspat wrote: post #11

Earlier quoted context omitted.

That is astounding! something I was unaware about before. At what depth could it be measured?

Almost any depth. A big steel tube is going to displace water. Once you have some baseline measurements (of known underwater landforms), then small imperceptible variations would stick out.

Not possible. The uncertainty of bathymetry in areas only mapped using gravity is larger than the dimensions of a sub.

Even in very well mapped areas, think of the effort in the Indian ocean to find MH370, this would require the assumption that the sub is moving, which is not always the case, e.g. if the sub halts propulsion and drifts with a current.

Re: A New Satellite Can Peer Inside Buildings, Day or Night

#85

Post by Drdrdrq » Thu, Dec 17, 2020, 9:38 PM UTC

baybal2 wrote: post #79

unchocked wrote: post #71

Note that these 50cm image resolutions are limited by law, not technology. The US military of course has superior technology, and its resolution is unlikely to be limited by statute. The NRO Topaz satellites are the successful radar development of the two prong Future Imaging Architecture (the optical component failed, which was to be the successor to Keyhole [of which the Hubble Space Telescope is derived]) should b…

> Note that these 50cm image resolutions are limited by law, not technology. By physics, and computing power. For any stable circular orbit, a satellite can only fly that fast, and the radio window would only pass so much of radio spectrum.

Except that they are only recording and transmitting data for a limited number of areas. Still a challenge though, I agree.

Re: A New Satellite Can Peer Inside Buildings, Day or Night

#86

Post by EricE » Thu, Dec 17, 2020, 9:40 PM UTC

giantg2 wrote: post #67

credit_guy wrote: post #28

Earlier quoted context omitted.

> governments [...] could easily inspect "their" people Governments can now spy on their people via old fashioned surveillance: wire-tapping, informants, social media analysis, etc. If a nation has the checks and balances to prevent that, then it's very likely they'll be able to prevent satellites peeking into your home. If not, it could potentially be another tool in their oppression toolkit, but not terribly effici…

There may not be specific laws preventing this sort of surveillance because it is unknown. Sure, you could have it considered as a general 4th ammendment violation which would protect the general population. You'll still have it used against small numbers of high-value targets. I think the main thing preventing widespread use is that once you start using these technologies on a larger scale, then people can identify…

Even if there were laws would they bother to comply? I’m still shocked by how little people understand what Snowden exposed about what the NSA is already doing - if you are concerned about these satellites you should be even more concerned about the other crap already going on that we KNOW the NSA has been lying about.

Re: A New Satellite Can Peer Inside Buildings, Day or Night

#87

Post by unchocked » Thu, Dec 17, 2020, 11:16 PM UTC

baybal2 wrote: post #79

unchocked wrote: post #71

Note that these 50cm image resolutions are limited by law, not technology. The US military of course has superior technology, and its resolution is unlikely to be limited by statute. The NRO Topaz satellites are the successful radar development of the two prong Future Imaging Architecture (the optical component failed, which was to be the successor to Keyhole [of which the Hubble Space Telescope is derived]) should b…

> Note that these 50cm image resolutions are limited by law, not technology. By physics, and computing power. For any stable circular orbit, a satellite can only fly that fast, and the radio window would only pass so much of radio spectrum.

From the article, the 50cm resolution is by law. Physical limits also exist, and one presumes that military hardware is operating closer to them.

Re: A New Satellite Can Peer Inside Buildings, Day or Night

#88

Post by unchocked » Thu, Dec 17, 2020, 11:27 PM UTC

baybal2 wrote: post #77

aerostable_slug wrote: post #70

Earlier quoted context omitted.

Tracking submerged boats from space is the holy grail of ASW, and as best as I can tell it doesn't work outside littoral zones (where sometimes you can optically detect the sub) and contrived tests. It has been tried with SAR, blue/green lasers, IR, all kinds of stuff, and luckily it doesn't work in the real world. When it does, it will be massively destabilizing as it places the "invulnerable" second strike capabili…

> When it does, it will be massively destabilizing as it places the "invulnerable" second strike capability that guarantees deterrence against peer states at risk. It never been such to begin width, at least by the late cold war, some portion of missile subs were reliably tailed by adversaries without any high tech trickery. North Korea, Russia, and China each already have more submarines than USA, and would have no…

Tailing some portion of missile subs won't do - a single missile sub is an existential threat so deterrence isn't destabilized until the adversary can credibly eliminate all of them within ~10 minutes.

It takes a nuclear sub to trail a nuclear sub. NK and China have exclusively, and primarily (respectively) diesel subs. These have to surface and run their engines to charge batteries. They cannot make 20+ knots submerged for long, and they cannot track deeply submerged submarines from the surface. Surfacing and running diesels would make their presence known. They cannot range far from port, and certainly cannot track missile boats under the arctic ice.

Russia has a sufficiently large nuclear fleet, but it is outdated and probably outclassed by US technology. There is probably greater disparity between the powers than existed during the cold war, at which time deterrence was credible.

Re: A New Satellite Can Peer Inside Buildings, Day or Night

#89

Post by dzhiurgis » Fri, Dec 18, 2020, 1:42 AM UTC

walrus01 wrote: post #66

leoedin wrote: post #20

Earlier quoted context omitted.

If you want to block SAR, just set up a big corner reflector near you. It'll completely blind the part of the image near you. It would also draw a lot of attention to you... So maybe not the best approach if you're trying to hide.

or a whole bunch of small corner cube reflectors (such as you would see attached to a sailboat mast for intentional greater radar visibility) in a grid like array. https://www.westmarine.com/WestAdvisor/Selecting-a-Radar-Ref...

Wonder if someone uses this tech for monitoring entire ocean, not just narrow spots.

Similarly there's monitoring of AIS by Iridium, but pirates and drug lords turn those off.

Re: A New Satellite Can Peer Inside Buildings, Day or Night

#90

Post by geomark » Fri, Dec 18, 2020, 5:25 AM UTC

raws wrote: post #17

a3n wrote: post #16

Earlier quoted context omitted.

Your linked article says that satellite's company is Finnish, not US.

I think he's just alluding to the fact that there's already better ones out there for other countries, maybe even better for secret military bodies.

That's right. The article says "...other SAR satellites on the market can only get down to around five meters" which isn't true if the story I linked is accurate.