A second satellite, the Atmospheric Neutral Density Experiment (ANDE-2), is part of a United States Department of Defense project flown by the Naval Research Laboratory to provide high-quality satellites, and will measure the density and composition of the low Earth orbit atmosphere while being tracked from the ground, to better predict the movement and decay of objects in orbit. ANDE-2 consists of two spherical microsatellites, ANDE Active spacecraft (Castor) and the ANDE Passive spacecraft (Pollux), and will be tracked by the International Laser Ranging Service (ILRS) network as well as the Space Surveillance Network (SSN). One of the satellites, Pollux, is running Arduino libraries, with its payload programmed and built by students.