The ANDE MAA sphere is made from a proprietary alloy of AL 6061 that is castable, while the FCAL sphere is made from brass. The ANDE FCAL sphere has the distinction of being the only micro satellite to have its structure composed primarily of brass. The differences in materials and hence density and mass of the spheres will cause them to separate from each other along track over time. This separation will be measured and compared to predicted models of where the satellite should be based on computed models of the space environment.