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There are whole ships powered by the magnus effect:

https://en.wikipedia.org/wiki/Rotor_ship

They’re sails in this configuration—nothing more. They harness existing force of wind. They get spun up and if they spin the right way they produce a force perpendicular to the wind.

The magnus effect is a byproduct of laminar flow of fluid/air around a spinning object. Without laminar flow there is no force. So that is to say if you spin a sphere really fast and it’s hovering in air without gravity and without wind it will not move because there will be no laminar flow to produce the magnus effect. So in order for your spherical craft to actually harness the magnus effect you would need a separate means of propulsion to drive you in the primary direction and harness the magnus effect for thrust in a secondary direction, ie turn.

Did some more research, you seem to be right. Although the design I proposed could still be viable--when the wind is still the sphere would simply hover, and when the wind is blowing the sphere could move controllably, just not against the wind. At 10k feet there should be sufficient wind to control the sphere most of the time.

None of what are an sphere.

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