An aero-spacecraft for the far upper atmosphere supported by microwaves

We propose a new type of air/space craft, supported from below at altitudes ∼70km by a 'radiometric' temperature-difference effect. From there it can perform communications relay, environmental monitoring, data telemetry and high-quality optical imaging. We show that an ultralight, mostly carbon-fiber “Lifter” is feasible using the radiometric force, an effect known since the 19th century, in combination with optimized properties of known carbon fiber materials. A powerful microwave beam illuminates the Lifter underside to provide the required temperature difference. Optimally, the full ambient atmospheric pressure can be delivered to one side of the Lifter area by heating it well above the ambient air at 200 K. Beam powers of ∼MW can support masses of ∼100kg. We verified the magnitude and pressure dependence of the effect on carbon fiber disks heated by microwaves in laboratory experiments. Numerical simulations suggest that carbon fiber craft of certain shapes can provide passive stability while riding a narrow microwave beam, and active stabilization is available through beam manipulation.