[rolling_robot]

I am curious how are you planning to cope with aeroelasticity issues in near-earth turbulence. Given low air speed, low wing loading, and huge aspect ratio this is going to be an issue. I suspect that most of the previous projects failed because of these issues combined with tight requirements on very light-weight structures.

[t0mas88]

Indeed. Very high aspect ratio wings could be hard to make strong enough at very low weight to survive climbing through the lower parts of the atmosphere.

Some convective activity could help the climb, but it would add a lot of turbulence for the first 30,000ft or so.