Daedalus plans to explore the mesosphere — the levels of the atmosphere between 50 and 100 km up, inaccessible to balloon or satellite. His plan is to make a giant helicopter rotor based on the principle of the Crookes radiometer. One side of each blade is painted black, the other white. The black side, warmed by the Sun, will give a bigger thermal kick to impinging air molecules than the white side, so the whole rotor will rotate. Altoradiometers will soon be hovering in the mesosphere, migrating polewards as they collect valuable scientific data.
