What are the regulations on flying UAVs (commercial or experimental) above FL600, i.e. in class E airspace above class A? I want to make a HAPS (High Altitude Pseudo Satellite) and operate it in the higher altitudes.
Is there a way to do this without a pilot's license (I don't know if I can pass TSA background checks)? How high do I have to fly to be above class A and in the class E airspace? Would you recommend launching from international waters? And how high should I fly to be in space or in completely unregulated and uncontrolled airspace?
Cannot be flown higher than 400 feet above ground level (AGL), unless
flown within a 400-foot radius of a structure and does not fly higher
than 400 feet above the structure’s immediate uppermost limit;
To fly your own Unmanned Vehicle in national airspace without a chase plane you need a Certificate of Authorization for that UAV. See this article here about the Global Hawk which flies above 60,000 feet. I have no idea how you would go about getting that authorization but I am sure that it won't be trivial. Global Hawk was tested in restricted military airspace before approval was granted to fly in national airspace. And yes you would need a remote pilot certificate to operate the UAV see details from the AOPA here. So you need two things to fly in national airspace: To certify the aircraft and to get a remote pilot certificate to pilot it.
Testing in International waters would be feasible since international waters is unregulated airspace but you still need to be careful to avoid any international traffic. The best thing to do is contact the FAA and see what they say about it. The FAA can be very flexible on accommodating experimental aircraft so it never hurts to ask.