[Astrobee] will be powered differently, too. A space drone does not need to work to keep itself airborne. Like the rest of the space station it is in free-fall and thus appears to float with respect to the station’s walls. But it does need motors of some sort to move itself around.
SPHERES use jets of carbon dioxide to propel themselves, and the canisters that this gas is stored in must be shipped to the station, changed by the astronauts and returned to Earth for refilling. The Astrobee, by contrast, will compress air on board, using battery power, and employ that for propulsion. To top up its batteries for this and other purposes, it will also be able to steer itself to one of several recharging docks.
It astounds me that people forget about the ISS and the work that NASA is doing up there. They invent amazing things, do a lot of pure-science research, and are just cool to boot.