NASA's Magnetospheric Multiscale (MMS) mission was launched on 13 March 2015 from Cape Canaveral, Florida on board an Atlas V rocket. The goal of the mission is to study the dynamics of the Earth's magnetosphere and the underlying energy conversion processes. The mission consists of four identically equipped spacecraft flying in formation which are able to measure plasma processes in the Earth's magnetosphere fully in three dimensions. The MMS satellites build on the successes of the ESA's Cluster mission. In contrast to Cluster, the MMS spacecraft fly in a smaller formation allowing the physics of small scale processes to be investigated. MMS are also on a different orbit allowing other areas of near-Earth space to be explored. IWF is the mission's largest non-American partner.
The focus of the mission is on magnetic reconnection; a process where magnetic energy is converted into particle energy. Magnetic reconnection is a key physical process in a number of different phenomena such as in magnetic storms which are related to the northern lights on Earth. The fast time resolution of the instruments and the small separations of the multiple spacecraft are essential for distinguishing between temporal and spatial changes in the plasma. These properties of the mission allow a detailed investigation of reconnection's smallest scales fully in three dimensions. From the MMS data, our knowledge about the Sun and its influence on the Earth and the solar system will be significantly expanded.
NASA has entrusted the mission to the Southwest Research Institute (SwRI), San Antonio, USA. The payload consists of the most extensive set of fast particle and field measurement instruments to date. These include the FIELDS instrument package for measuring electromagnetic fields, each with several sensors, three instrument packages for particle measurements (with a focus on high time resolution, composition and high-energy particles) as well as instruments for regulating the satellite potential.