Airbus’ solar-powered Zephyr S has been flying non-stop for more than 17 days

It can fly at an altitude of 76100 feet which is not far from the altitude at which spy planes like the SR-71 were flying. With its small size, I wonder how detectable it would be flying over a hostile zone.

Given that they seem to have troubles spotting consumer drones flying at a few hundreds meters spotting for artillery in Ukraine, I imagine it might be hard to spot such a UAV at 23km high.

I suppose it could be a great military asset: able to stay undetected hovering above an area of interest at an order of magnitude lower altitude than common spy satellite.

Back in 2018, Zephyr stayed in the air for close to 26 days: https://www.airbus.com/en/newsroom/press-releases/2018-08-ai...