Workers inspect the solar arrays on the Magnetospheric Multiscale, or MMS, observatories in the Building 1 D high bay of the Astrotech payload processing facility in Titusville, Florida, near Kennedy Space Center. The two MMS spacecraft comprising the upper deck arrived Nov. 12; the two comprising the lower stack arrived Oct. 29. MMS, led by a team from NASA's Goddard Space Flight Center, is a Solar Terrestrial Probes mission consisting of four identically instrumented spacecraft that will use Earth’s magnetosphere as a laboratory to study the microphysics of three fundamental plasma processes: magnetic reconnection, energetic particle acceleration and turbulence. Launch aboard a United Launch Alliance Atlas V rocket from Space Launch Complex 41 on Cape Canaveral Air Force Station is targeted for March 12, 2015.