[nosequel]

This looks like a great project. Global Hawk [1] has all the current autonomous aircraft records (longest autonomous flight, etc.). Obviously you can't go as fast as Global Hawk, but one great thing is you don't have to worry about all the issues around fuel freezing. To at least some of our surprise, 60k+ feet around the equator was much colder than 60k+ feet around Edwards AFB and we approached the freezing limits of jet fuel.

The downside is you don't have any fuel to cycle through the computers for cooling and forced air becomes a big problem at high altitude. I'm sure you've thought about it, but what atmosphere do you plan to keep the cabins at?

Good luck on your project! Working on autonomous vehicles like Global Hawk and our DARPA Grand Challenge vehicle was one of the highlights of my career.

- [1] https://en.wikipedia.org/wiki/Northrop_Grumman_RQ-4_Global_H...

[H8crilA]

That record is only ~23 hours because it is a record within a very heavy weight class (14,000 kg+). There are many crafts similar to the one presented here that have done multi-day flights. This one can fly for months at a time: https://www.airbus.com/en/products-services/defence/uas/uas-.... And you can track it real time via ADS-B when it's up there!

Speaking of ADS-B, how do you get airspace clearance? And what do you need to have, voice comms / ADS-B? I guess there's not much of a problem with that given that next to no one flies so high.

[nosequel]

Clearance was really hard back in 2002 when Global Hawk was coming out of test phase and into production. There wasn't another autonomous plane, so it was the first to do what it was trying to do. That wasn't really my field, but I know it was truly painful to get FAA approval for lots of things. They were really concerned with some autonomous plane flying over cities, so most of our long flights avoided flying over populations. That was pretty easy in CONUS, but flying into Germany for the Euro Hawk was super painful apparently. There isn't exactly un-populated areas around there. Regarding voice, yes there was someone in the ground station on comms, and to any other airplane, they appeared to be coming from the aircraft and not the ground. Altitude makes a lot of things easier, plus the military has a lot of restricted airspace. I honestly have no idea how a civilian autonomous aircraft will pull it off. I'm sure a lot has changed in 20-ish years, so maybe it is not a painful now. With the FAA, I'm sure it'll still be a headache.