The mission builds upon the successes of the ESACluster Mission, but will surpass it in spatial resolution and in temporal resolution, allowing for the first time measurements of the critical electron diffusion region, the site where magnetic reconnection occurs. Its orbit is optimized to spend extended periods in locations where reconnection is known to occur: at the dayside magnetopause—the place where the pressure from the solar wind and the planets' magnetic field are equal—and in the magnetotail—which is formed by pressure from the solar wind on a planet's magnetosphere and which can extend great distances away from its originating planet.
Magnetic reconnection in Earth's magnetosphere is one of the mechanisms responsible for the aurora, and it is important to the science of controlled nuclear fusion because it is one mechanism preventing magnetic confinement of the fusion fuel. The study of turbulence in outer space involves the measurement of motions of matter in stellar atmospheres, like that of the Sun, and magnetic reconnection is a phenomenon in which energy is efficiently transferred from a magnetic field to charged particles.
The principal investigator is James L. Burch of Southwest Research Institute, assisted by an international team of investigators, both instrument leads and theory and modeling experts. The Project Scientist is Thomas E. Moore of Goddard Space Flight Center. Education and public outreach is a key aspect of the mission, with student activities, data sonification, and planetarium shows being developed.
The mission was selected for support by NASA in 2005. System engineering, spacecraft bus design, integration and testing has been performed by Goddard Space Flight Center in Maryland. Instrumentation is being improved, with extensive experience brought in from other projects, such as the IMAGE, Cluster and Cassini missions. In June 2009, MMS was allowed to proceed to Phase C, since they passed their Preliminary Design Review. The mission passed its Critical Design Review in September 2010. The spacecraft will launch on an Atlas V 421 rocket, scheduled for 26 November 2014 and no later than March 2015.
In order to collect the desired science data, the four satellite MMS constellation must maintain a tetrahedral formation through a defined region of interest in a highly elliptical orbit. The formation will be maintained through the use of a next generation space rated GPS receiver, Navigator, to provide orbit knowledge, and regular formation maintenance maneuvers.
Sharma, A. Surjalal; Curtis, Steven A. (2005). "Magnetospheric Multiscale Mission". Nonequilibrium Phenomena in Plasmas. Astrophysics and Space Science Library 321. Springer Netherlands. pp. 179–195. doi:10.1007/1-4020-3109-2_8. ISBN978-1-4020-3108-3.
National Research Council (2003). The Sun to the Earth - And Beyond. National Academies Press. ISBN978-0-309-08972-2.