The CubeSat program began in 1999 as a collaboration between California Polytechnic State University and Stanford University. The goal was to design a standard for picosatellites, tiny Earth-orbiting boxes usually with a volume of about 61 cubic inches (1 liter) and a mass of about 2.9 lbs. (1.33 kilograms).
CubeSats are built in a variety of sizes, from 1U (one unit) up to three-plus units. Rails on the edges smooth the ride as the satellite is ejected from the P-POD deployer. Rectangular access doors are arrayed down the side of the satellite.
Future CubeSats will go deeper into space than any CubeSats have gone before.
INSPIRE (Interplanetary NanoSpacecraft Pathfinder In Relevant Environment): The first cubesats to be boosted out of Earth orbit, INSPIRE will orbit up to 930,000 miles (1.5 million kilometers) from Earth during a three-month mission.