The STP-2 payload is composed of 25 small spacecraft. Included is COSMIC-2 constellation to provide radio occultation data, along with 8 cubesat nanosatellites. Other payloads include LightSail carried by the Prox-1 nanosatellite, Oculus-ASR nanosatellite, GPIM and the Deep Space Atomic Clock.
Space Exploration Technologies Corp., known as SpaceX, is an American aerospace manufacturer and space transport services company headquartered in Hawthorne, California. It was founded in 2002 by entrepreneur Elon Musk with the goal of reducing space transportation costs and enabling the colonization of Mars. SpaceX has many pads, on the East Coast of the US they own SLC-40 at Cape Canaveral and LC-39A at the Kennedy Space Center for their lower inclination launches. They also own SLC-4E at Vandenberg, California for their high inclination launches. Another site is also being developed at Boca Chica, Texas.