James A. Slavin

Climate & Space Professor and Chair

Department of Climate and Space Sciences and Engineering, College of Engineering, University of Michigan

Space Missions


MESSENGER Mission Credit: NASA

The flybys of Mercury by the Mariner 10 and MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft have shown that the planet’s internal magnetic field is largely dipolar, aligned with the spin axis, and of the same polarity as Earth’s field. The solar wind interaction with the planetary magnetic field causes a portion of Mercury’s magnetic field to be swept downstream to form a planetary magnetic tail (i.e. “magnetotail”). Initial analyses of the MESSENGER measurements showed that the magnetic fields in Mercury’s tail varied greatly from one flyby to the next and to exhibit dynamic variations on time scales of seconds to minutes. Prof. Slavin is a MESSENGER Co-Investigator and he chairs of the Atmosphere and Magnetosphere Discipline Group. Details of the MESSENGER instrument payload and mission plan can be found online at http://www.nasa.gov/mission_pages/messenger/main/index.html

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Magnetospheric MultiScale

Magnetospheric MultiScale Mission Credit: NASA\GSFC\Lambert

The Magnetospheric MultiScale (MMS) mission now in development will use simultaneous measurements from a four spacecraft observatory to discover the nature of the plasma instabilities that lead to the rapid conversion of magnetic energy to charged particle flow and heating in space plasma current sheets. This energy conversion process, termed “magnetic reconnection”, is especially important for magnetospheres where it enables solar wind energy to be stored by planetary magnetic fields and, later, released explosively in the form of “storms” and “substorms.” Prof. Slavin is a Science Co-Investigator and member of the magnetometer team. Details of the MMS instrument payload and mission plan can be found at mms.gsfc.nasa.gov/

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BepiColombo Mission Credit: ESA

The Mariner-10 discovery in 1974 of an intrinsic though reduced magnetic field at Mercury suggests that a magnetosphere forms around this planet with characteristic spatial and temporal scales much smaller than those at Earth. Investigation of a magnetospheric system with such widely different scales is of interest both for properties of its own and for comparison with plasma processes in other planetary environments. These processes include the source/sink and acceleration of magnetospheric particles, the stability of the plasma sheet, the possibly abrupt release of magnetic energy via reconnection at the magnetopause and in the magnetotail, or the dynamical reconfiguration of magnetic field lines during substorms. BepiColombo is a joint mission between ESA and JAXA that is scheduled for launch in 2014 and arrival at Mercury in 2020. This two spacecraft mission will conduct a detailed investigation of the structure and dynamics of Mercury’s magnetosphere. Particular emphasis will be placed upon Mercury’s complex particle environment. Magnetospheric charged particles are expected to be closely coupled to the highly variable neutral atom exosphere produced by the sputtering at the surface of the planet in regions impacted by solar wind protons. Photo-ionization of these neutrals as well as charge exchange and direct surface release processes will all contribute to the magnetospheric plasma populations.  Prof. Slavin is Co-Investigator on the Magnetometer and STROFIO investigations that will explore the magnetic structure of the magnetosphere and the composition and dynamics of the neutral atmosphere, respectively.  More information about the BepiColombo mission can be found online at:  sci.esa.int/science-e/www/area/index.cfm?fareaid=30

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Europa Clipper Mission

JUICE Mission Credit: NASA

Europa Clipper will explore Europa focusing on its: 1) Ice shell and ocean: Confirm the existence, and characterize the nature, of water within or beneath the ice, and processes of surface-ice-ocean exchange; 2) Composition: Distribution and chemistry of key compounds and the links to ocean composition; and 3) Geology: Characteristics and formation of surface features, including sites of recent or current activity. The Clipper will not orbit Europa, but instead conduct between 32 to 48 flybys of Europa at altitudes from 25 to 2700 km. Each flyby would cover a different sector of Europa in order to achieve a medium-quality global topographic survey, including ice thickness. The Europa Clipper will also fly at low altitude and pass through the plumes of water vapor erupting from the moon's icy crust.  Prof. Slavin is Co-Investigator on the Plasma Instrument for Magnetic Sounding (PIMS), the principal investigator being Dr. Joseph Westlake of Johns Hopkins Applied Physics Laboratory . This instrument works in conjunction with a magnetometer and is key to determining Europa's ice shell thickness, ocean depth, and salinity by correcting the magnetic induction signal for plasma currents around Europa.  Europa Clipper is expected to launch as early as 2022 and arrive at Europa in 2025.  More information on the Europa Clipper Mission can be found at en.wikipedia.org/wiki/Europa_Clipper

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JUICE Mission Credit: ESA

The Jupiter ICy moon Explorer (JUICE) mission will investigate Ganymede with special focus on its ability to support life. Magnetic field and gravity measurements will be used to characterize and model this moon's internal ocean. Ganymede's surface will be mapped and its composition determined. The magnetosphere formed by the interaction of this moon's intrinsic magnetic field and Jupiter's co-rotating plasma disk will be explored. Before its final injection into an orbit about Ganymede JUICE will carry out multiple flybys of Callisto and Europa and collect extensive measurements of Jupiter's magnetosphere. Prof. Slavin is Co-Investigator on the Magnetometer investigation that will characterize Ganymede's magnetic field and its plasma environment. If all goes as planned, the spacecraft will arrive at Jupiter in 2030.

More information about the JUICE mission can be found online at sci.esa.int/juice

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