NASA\u27s Four Spacecraft Magnetospheric Multiscale Mission

The Magnetospheric Multiscale (MMS) mission is a Solar Terrestrial Probes Program mission within NASA’s Heliophysics Division. The mission consists of four identically-instrumented spin-stabilized satellites that will be placed, with surgical accuracy, into the heart of Earth’s magnetic reconnection regions. A mono-propellant propulsion system with 12 thrusters on each 1250 kg spacecraft will execute both small formation maintenance maneuvers and large apogee raise maneuvers – achieving controlled interspacecraft separations down to 10 km at mission-phased Earth-constellation distances eventually reaching 160,000 km. Each probe carries 25 sophisticated scientific instrument systems including those mounted to the 8 deployable booms. An attitude control system keeps the spacecraft to within ±0.5° of the desired orientation using on-board closed loop maneuver control. Scientifically, the MMS mission will utilize Earth’s natural plasma laboratory to conduct the first sufficiently detailed measurements within an astrophysically ubiquitous phenomenon to solve the microphysics of magnetic reconnection. Magnetic reconnection is a fundamental plasma physical process that taps the energy stored in a magnetic field and explosively converts it to particle kinetic energy. This process occurs throughout the universe including, in all likelihood, star-accretion disk interactions, neutron star magnetospheres, pulsar wind acceleration. It is implicated in the acceleration of ultra-high-energy cosmic rays in active galactic nuclei jets and occurs in solar flares and solar Coronal Mass Ejections producing energetic charged particles that rain down on Earth’s environment. Fortunately, magnetic reconnection also occurs deep within Earth’s geospace environment, readily reachable by spacecraft, and thus can be examined directly by MMS. The four spacecraft in this “constellation” mission are nearing completion and entering testing, in preparation for an October 2014 launch on an Atlas-V 421 Launch Vehicle. During the development process the mission team has learned important, and frequently unexpected, lessons unique to developing multi-spacecraft missions. The speaker is representing hundreds of scientists, engineers, technicians, and managers that have brought the MMS mission to reality over the course of nearly one decade from concept to nearly the eve of launch