The Magnetospheric Multiscale Constellation

Abstract

The Magnetospheric Multiscale (MMS) mission is the fourth mission of the Solar Terrestrial Probe (STP) program of the National Aeronautics and Space Administration (NASA). The MMS mission was launched on March 12, 2015. The MMS mission consists of four identically instrumented spin-stabilized observatories which are flown in formation to perform the first definitive study of magnetic reconnection in space. The MMS mission was presented with numerous technical challenges, including the simultaneous construction and launch of four identical large spacecraft with 100 instruments total, stringent electromagnetic cleanliness requirements, closed-loop precision maneuvering and pointing of spinning flexible spacecraft, on-board GPS based orbit determination far above the GPS constellation, and a flight dynamics design that enables formation flying with separation distances as small as 10 km. This paper describes the overall mission design and presents an overview of the design, testing, and early on-orbit operation of the spacecraft systems and instrument suite.

How many solar wind data are sufficient for accurate fluxgate magnetometer offset determinations?

“…The MMS spacecraft are equipped with instruments to measure particle distribution functions (Pollock et al, 2016;Young et al, 2016;Mauk et al, 2016;Blake et al, 2016;Torkar et al, 2016) as well as electric and magnetic fields (Torbert et al, 2016a;Russell et al, 2016;Le Contel et al, 2016;Ergun et al, 2016;Lindqvist et al, 2016;Torbert et al, 2016b). Here, only measurements by the MMS fluxgate magnetometers (FGMs) are used.…”

“…Here, only measurements by the MMS fluxgate magnetometers (FGMs) are used. Each spacecraft has two fluxgate magnetometers, an analog fluxgate and a digital fluxgate magnetometer (AFG and DFG), mounted at the ends of two separate 5 m long booms (Torbert et al, 2016a;Russell et al, 2016). The instruments and, in particular, the offsets pertaining to AFG and DFG on all spacecraft are very well calibrated: as the MMS spacecraft are spinning, the spin plane offsets can be and are dynamically adjusted in low fields, e.g., in the solar wind (Bromund et al, 2016; Plaschke Figure 1.…”

Four‐Spacecraft Measurements of the Shape and Dimensionality of Magnetic Structures in the Near‐Earth Plasma Environment

“…In particular, when performing our analysis on MMS data, we exploit position measurements (Tooley et al, 2015) interpolated onto the magnetic field recorded by the FluxGate Magnetometer (FGM, Russell et al, 2016), sampled with an accuracy of 0.1 nT at 8 Hz for "slow survey" mode intervals, at 16 Hz for "fast survey" mode and at 128 Hz for "burst" mode. Given these instrumental accuracies, the precision of MCA results has been tested by a bootstrap-like procedure, that is by confronting values of MCA quantities found for some interval with those obtained on the very same input data but perturbed randomly inside their uncertainty to the black point would appear, given the local magnetic configuration suggested with blue arrows.…”

Electrodynamic context of magnetopause dynamics observed by magnetospheric multiscale

“…A primary objective of the Magnetospheric Multiscale (MMS) mission is to understand magnetic reconnection at Earth's magnetopause and in the magnetotail [ Burch et al ., ]. Launched on 12 March 2015, the mission achieves breakthrough observational capabilities with high‐rate field and plasma observations and state‐of‐the‐art navigation of the four MMS observatories [ Tooley et al , ; Fuselier et al , ]. It is important to relate MMS observations to magnetosphere–ionosphere (MI) dynamics.…”