NASA launched the Magnetospheric Multiscale, or MMS, mission on March 12, 2015. MMS consists of four identical spacecraft that orbit around Earth through the dynamic magnetic system surrounding our planet to study a little-understood phenomenon called magnetic reconnection.
Magnetic reconnection is a phenomenon unique to plasma, that is, the mix of positively and negatively charged particles that make up the stars, fill space and account for an estimated 99 percent of the observable universe.
MMS will travel directly through areas near Earth known to be magnetic reconnection sites. On the sun-side of Earth, reconnection can link the sun’s magnetic field lines to Earth’s magnetic field lines, allowing material and energy from the sun to funnel into Earth’s magnetic environment. On the night side of Earth, reconnection is believed to help trigger aurora, also known as the northern and southern lights.
Reconnection occurs when magnetic field lines cross and release a gigantic burst of energy. It is a fundamental process throughout the universe that taps energy stored in magnetic fields and converts it into heat and energy in the form of charged particle acceleration and large-scale flows of matter. However, magnetic reconnection can only be studied in situ in our solar system and it is most accessible in near-Earth space, where MMS will study it.
Several spacecraft, such as THEMIS and Cluster, have already sent back tantalizing data when they happened to witness a magnetic reconnection event in Earth’s magnetosphere, but besides MMS, no mission is currently dedicated to the study of this phenomenon.