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Comment by dhx | Hacker News Reader

"It's designed to capture 5km-wide spot scenes on the ground and have a best resolution of 90cm."[1]

Some sample ~90cm-ish imagery from Airbus Vision-1 (20km swath 87cm resolution) is available at [2].

It looks like it'd be used for knowing when a warship is in port (but perhaps having to guess which one), or when a warship under construction has been floated, or when a large military construction project has started or completed, or when ground for a new military forward operating base has been cleared, etc. Then more expensive higher resolution imagery could be ordered if it were worthwhile to do so.

[1] https://www.bbc.com/news/articles/c1d77yq9zz2o

[2] https://intelligence.airbus.com/newsroom/satellite-image-gal...

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90cm resolution is more than enough to identify a ship. There arent manu military ships in this world. All appear in public regularly . 90cm is enough to get overall hull dimensions and thereby separate a ship from its neighbours in port. They dont need to be read license plates. Ships are very big.

90cm would maybe be more susceptible to decoys (like the WWII inflatable tanks but with ships?)

Decoys are harder to fake, for instance an inflatable tank doesn't emit much infrared compared to a real tank. This was not an issue for camera that only capture visible light such as what was available in WWII or the naked eye.

Plus the ship can't appear suddenly in the middle of the ocean. And where do you hide the original ship?

Well... https://en.m.wikipedia.org/wiki/HNLMS_Abraham_Crijnssen_(193...

But my point is that when you have a satellite tracking a slow moving ship every 3-4 hours, it's impossible to hide it.

It's easier in space because of no air resistance, but stuff like mylar balloon/sheath decoys I think beats out basically all missile defense. Aside from the infrared stuff, inflatable ships not in port wouldn't leave an actual wake of the right size etc. and might not be viable.

from: https://www.inflatechdecoy.com/features/

" 01_OPTICAL SIGNATURE - LIFE SIZE, PERFECT SHAPE AND LIGHTWEIGHT

02_RADAR SIGNATURE - ALL YOU NEED TO DO IS UNPACK THE DECOY AND TURN ON THE ENGINE. 90 SECONDS LATER THE DECOY GENERATES YOUR DESIRED RCS.

03_INFRARED SIGNATURE - INFLATECH DECOYS CONTAIN INTEGRATED THERMAL SIGNATURE MANAGEMENT SYSTEM. WE GUARANTEE 100% MULTISPECTRAL COPY OF THE DESIRED SIGNATURE."

> This was not an issue for camera that only capture visible light such as what was available in WWII

It wasn't as common as today but we already had IR aerial photography in the 40s

Yes to 90cm being used for identifying the class of a ship. But probably no for 90cm being used for identifying a particular hull, which may only be determinable with higher resolution imagery to confirm a hull-specific feature such as an upgraded radar or gun.

Do we have good reasons to suppose this isn't a lie?

Absent that, I would expect the 2-3x on what's made public.

The vendor tells us that Tyche is supposedly derived from their existing carbonite satellites.

The carbonite product page broadly lines up with the claimed specs (~5km swath, ~1m resolution). At the claimed orbit (500km), a ~0.5m aperture (see "washing machine sized") is diffraction limited at about 0.7m, so there doesn't appear to be too too much wiggle room.

Side note - carbonite doesn't just do imagery - it does video too (https://www.youtube.com/watch?v=Sf_zd9MvW44).

https://www.sstl.co.uk/space-portfolio/missions-in-build/202...

https://www.sstl.co.uk/getmedia/b38389d7-cb07-4308-944a-a916...

The effective resolution is limited by the atmosphere as far as I understand. Eddies etc.

Also this satellite was very cheap at 22 million, the US cutting edge ones are rumoured to cost over a billion (and they're much bigger than washing machine size). So I wouldn't expect it to be a lot better than what's commercially available.

Why would you think it is a lie? Planet Labs' SkySat satellites have been flying for a decade and have 30cm resolution. The UK ones are based on existing Carbonite satellite that do 90cm.

If anything, having only 90cm when could be better is the odd thing.

> If anything, having only 90cm when could be better is the odd thing.

Seems you found the answer to your own question: it would be odd for it to be not better.

The other reason why it might be a lie is because the exact specs of spy gear is often kept secret. It is very hard to disguise the fact that you have launched a satelite, but comparatively easy to keep it secret what exactly is on it.

With peacetime military and government procurement cycles what would be odd would be that it was close to current best in class, not other way around.

Anybody remember what the estimated resolution was on those undoctored satellite images Trump leaked a few years ago?

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