The link https://plus.google.com/u/0/events/cv1m6fasvccse8uvlnlk9n0gf4g is to sign up to attend the hangout, post questions ahead of time, and watch it when it happens on the 14th
Another way to ask questions during the event would be to tweet me at @edkellyus
It's an interesting experiment. Please sign up if you can and let others that might be interested know as well.
Also, as I mentioned previously, the StratoSolar solve for x moonshot video has got high ratings on the solve for x site. If you login you can rate the video in various ways. If you have not done this already, please do. https://www.solveforx.com/moonshots/stratosolar-edmund-kelly