Thanks! Sounds like you have lots of relevant experience in this domain. Would love to chat. E-mail is in my bio.

Thanks!

Yes, the stratosphere has some tough environmental challenges like these low temperatures. To retain enough battery capacity, heating elements are required. The same is true for other onboard electronics.

Interestingly, because the stratosphere’s air is so thin, heat generated by the aircraft isn’t lost as fast to the surrounding air as at sea-level.

As mentioned by th0mas88, humidity is pretty low and icing typically doesn’t occur at these altitudes.

Sounds awesome! Would love to chat, email in bio.

What about the power/weight budget, esp. for the 110 ft. wingspan aircraft mentioned above?

Low weight and high aerodynamic efficiency are crucial. You naturally end up with high aspect-ratio wings which tend to be more flexible than conventional aircraft wings. In order to keep aero-elastic effects under control, multiple tailplanes can help to stabilize the structure, and provide roll control at the same time - we’re not set on this technology though, ultimately our analysis tooling will drive this design decision.

Batteries are heavy, but if you want to conduct long endurance flights - greater than a few days, then realistically they are the best option.

Yeah Daniel made some really cool solar aircraft and other RC stuff! Love his channel. We talked to him in the early days of this project.