NASA has a challenge going and from what I’ve seen so far no one has won. The contest was on last year as well. I’ll try to get some details but this is the concept: Build an AUTONOMOUS platform that will stay stationary at an altitude of 65,000 feet for 20 hours carrying a 20 kilogram payload. And that’s all that required to win the award. The reward for accomplishing this is a million bucks:
The floor is open for discussion.