CubeSats are satellites constructed of cubic units, or U, a bit smaller than a square tissue box, or about 10 centimeters (about 4 inches) on each side. (A 2U CubeSat, for instance, is about the size of a rectangular tissue box.) Initially developed two decades ago as an inexpensive platform for students to learn about satellite development, CubeSats weren’t thought of as devices for collecting valuable data.