Possible/probable reasons why Perlan 2 is the best choice:

- Perlan 2 already exists.

And, hey, the made production-quality wing and fuselage tooling for it, so they can make more if they want!

- There are no electric UAVs with a similar flight envelope.

- Any powered replacement has to be electric to avoid atmospheric
exhaust contamination.

- Even an electric UAV will add unwanted disturbances with its prop wake.

This isn't about electric versus unpowered. It's about the necessity of doing this with a crewed vehicle. There is nothing in any of those arguments that supports carting two humans and several hundred pounds of life-support infrastructure around the sky.

I'm sure that there are valid arguments for having humans aboard so they can respond adaptively and innovatively to any flight or scientific situation that might arise. I simply don't buy the idea that doing so is best or even lowest-cost option. I think that a UAV, or a cooperative swarm of UAVs, or even a series of balloon-dropped UAVs, could do the planned research with a risk/reward ratio about an order of magnitude better.

--Bob K.