A few hours ago the four MMS (Magnetospheric Multiscale Mission) spacecraft were launched atop an Atlas V 421 rocket from Cape Canaveral. After nearly two hours the spacecraft started separating from the rocket’s last stage, one at a time at intervals of about five minutes. It’s only the beginning of a complex phase of tests, deployment of their booms with the sensors and positioning of the probes in a tetrahedron configuration which will last more than five months.

The MMS mission is really ambitious because it’s based on the work of a constellation of four identical spacecraft that will operate together in a tetrahedral formation in order to make three-dimensional measurements. The purpose is to study the magnetosphere in a way more sophisticated than those previously attempted.

In particular, the space probes will study the phenomenon of the magnetic reconnection. It’s a process in highly conductive plasma in which the magnetic topology is rearranged and the magnetic energy is converted into kinetic and thermal energy and into particle acceleration.