How Zipline Designed Its Droid Delivery System

About a year ago, Zipline introduced Platform 2, an approach to precision urban drone delivery that combines a large hovering drone with a smaller package-delivery “Droid.” Lowered on a tether from the belly of its parent Zip drone, the Droid contains thrusters and sensors (plus a 2.5- to 3.5-kilogram payload) to reliably navigate itself to a delivery area of just one meter in diameter. The Zip, meanwhile, safely remains hundreds of meters up. After depositing its payload, the Droid