[the_duke]

And stealth space platforms.

There might already be stealth sats in orbit.

A curious case was the Zuma satelite [1].

Classified payload. Ostensibly failed to detach from the payload adapter, as claimed by anonymous sources... Lot's of speculation that this was a media charade to sow confusion about a stealth sat.

[1] https://en.wikipedia.org/wiki/Zuma_(satellite)

[nradov]

There are no stealth satellites. It's impossible to hide in orbit due to power and cooling requirements.

http://www.projectrho.com/public_html/rocket/spacewardetect....

[wyager]

This is a funny claim to make given that the US literally has stealth satellites. https://en.wikipedia.org/wiki/Misty_(satellite)

Just because it's physically challenging to avoid having some blackbody emissions or whatever doesn't mean you can't evade modern sensors in practice.

[nradov]

What's your point? Those satellites were detected. They weren't actually stealthy in any meaningful way. Very minor signature reductions at best.

[wyager]

"That launch deposited a payload into geosynchronous orbit but, given the stealth/deception hypothesis, there remains the possibility of other, undetected payloads"

[nradov]

There remains a "possibility" that dinosaurs aren't extinct and they're hiding somewhere. Just because civilian astronomers haven't found such payloads doesn't mean those payloads actually exist. And hypothetically even if those payloads do exist it doesn't mean other nations haven't tracked them.

Wikipedia isn't a reliable source for this stuff. Look at the basic physics involved.

[angry_octet]

While amateurs can do an amazing job of detecting satellites, I think it is pretty likely that there are smaller satellites which are operating in extreme low power mode, waiting until a conflict where they are required. Whether there are enough to replace GPS and comms lost due to anti-satellite attacks and resulting debris is a bigger question.

[nradov]

It isn't physically possible to get useful GPS service from a small satellite. This is just basic physics. Calculate the power required to transmit the necessary signals. You need some fairly sizable solar panels. No way to hide those.

[mlyle]

I get crummy GPS fixes inside my house with 30dB+ of attenuation of the signal by structure and parts of the sky absolutely masked, while using absolutely crummy antennas.

To me, this seems to imply you could make a useful system today with orders of magnitude less transmit power.