Students from a dozen middle and high schools competed in the University of Southern Maine’s third annual CubeSat Design Competition on Saturday at Mt. Blue High School in Farmington. A balloon took student-designed microsatellites to an altitude of about 120,000 feet, with the launch testing mission planning, engineering design, and performance of the student-built cubesats (a class of small cube-shaped research satellites, often weighing less than 3 pounds).