Thread

The top secret URSALA, RAQUEL, and FARRAH satellites (2025)

306 points · 162 comments · Bluestein

Almondsetat · 1790809198 · focus · HN ↗
The incredible and futuristic technologies the US managed to deploy decades before the competition reminds me of the story of how the NRO gifted NASA a couple of their old decommissioned satellites in 2012 and they turned out to be basically upgraded Hubble telescopes pointed at earth. The US from the 90s to the 2000s had multiple Hubble-level telescopes just for spying while NASA was fighting for scraps to study the entire cosmos.
1. walrus01 · 1790812512 · focus · HN ↗
  We see a few bits and pieces released to the public of optical/infrared wavelength mirrors and hubble-like hardware from IMINT systems. One thing that's never really been shown to the public, not even 50 year old 1970s era stuff, are photos/examples of the SIGINT systems that the NSA likely has in orbit. Or good details of other things that also fall within the RF engineering domain like synthetic aperture radar satellites to monitor naval activity, construction activity like digging bunkers, etc.
  If you think the public DEM/DSM datasets like the ASTER GDER v3 or SRTM GL1 V3 are pretty good, I would bet that the DoD has things far more accurate than those as digital models of the surface and built environment of the earth's surface.
  1. throwaway456744 · 1790817094 · focus · HN ↗
    An RF domain where there seems to be a dearth of information is passive radar. (Kraken passive radar was shutdown.) It makes sense that NRO satellites would be doing passive SAR.
    walrus01 · 1790817244 · focus · HN ↗
    I'm not sure that it needs to be passive, a sufficiently advanced adversary nation-state (Russia, China) is assumed to have their own equivalent of this, and to be aware of the orbits of US satellites:
    <a href="https://en.wikipedia.org/wiki/United_States_Space_Surveillance_Network" rel="nofollow">https://en.wikipedia.org/wiki/United_States_Space_Surveillan...
    Much as the US is aware of the orbits of their satellites.
    If you already assume that it's hard to 'hide' the existence and orbits of your satellites from an advanced observer with good telescopes and ground radar and ways of correlating the data, the fact that your ocean surveillance satellites emit radar might not be a problem. No need to be passive about it.
    MegaDeKay · 1790823733 · focus · HN ↗
    And passive SAR is a lot less accurate than active SAR.
    There isn't much need for stealth in all this the same way there isn't for an optical spy satellite. The adversary knows it is there and what it is looking at. The adversary just doesn't know its exact capabilities, and there's not much they can do about it being up there that doesn't lead to a sudden military escalation of some kind.
    scottapotamas · 1790829577 · focus · HN ↗
    <a href="https://github.com/30hours/blah2" rel="nofollow">https://github.com/30hours/blah2
    someguydave · 1790856908 · focus · HN ↗
    This is because it is essentially illegal to work on proprietary VHF/UHF passive radar (you need a government license to talk about your work with foriegners) in the US due to itar laws
    NetMageSCW · 1790864422 · focus · HN ↗
    That doesn't make it illegal at all. Lots of what SpaceX does is covered by ITAR and they have no issues building rockets.

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