CyPhy's basic operating philosophy is that sophisticated robots are great, but that there is a huge untapped space for simpler robots that can get the job done without too much complexity getting in the way. EASE is a good example of this. It is tethered to a ground station by a fishing-line-thin wire that is fed out of the robot by an onboard spooler. That may sound like it limits range, and it does. But it also means EASE is powered from the ground. It doesn't have to carry a weighty battery and it can stay aloft indefinitely. And should the cable get cut, EASE won't fall out of the sky. An onboard backup battery can see it safely to the ground.