Magnetospheric Multiscale Mission

The mission builds upon the premise of the ESA Cluster mission, but MMS instrumentation surpasses it in spatial resolution and in temporal resolution, allowing for the first time measurements of the critical electron diffusion region, the site where magnetic reconnection occurs. Its orbit is optimized to spend extended periods in locations where reconnection is known to occur: at the dayside magnetopause, the place where the pressure from the solar wind and the planets' magnetic field are equal; and in the magnetotail, which is formed by pressure from the solar wind on a planet's magnetosphere and which can extend great distances away from its originating planet.

Magnetic reconnection in Earth's magnetosphere is one of the mechanisms responsible for the aurora, and it is important to the science of controlled nuclear fusion because it is one mechanism preventing magnetic confinement of the fusion fuel. These mechanisms are studied in outer space by the measurement of motions of matter in stellar atmospheres, like that of the Sun. Magnetic reconnection is a phenomenon in which energy may be efficiently transferred from a magnetic field to the motion of charged particles.{{cite journal|title=Microphysics of Magnetic Reconnection|journal=Space Science Reviews|first1=Andris|last1=Vaivads|first2=Alessandro|last2=Retinò|first3=Mats|last3=André|volume=122|issue=1–4|pages=19–27|date=February 2006|doi=10.1007/s11214-006-7019-3 |bibcode=2006SSRv..122...19V|s2cid=122892025 }}

File:Magnetospheric Multiscale Mission - NASA.webm

File:MMSPhase2b Pole Jan2May2017.UHD3840 2160p30.webm

The MMS mission consists of four spacecraft. Each has a launch mass of {{cvt|1360|kg}}. In their stowed launch configuration, each are approximately {{cvt|3.5|by|1.2|m}}, and when stacked together they have a total height of {{cvt|4.9|m}}. After being deployed in orbit, a total of eight axial and wire booms are deployed, including four Spin-Plane Double Probe (SDP) wire booms each {{cvt|60|m}} long.

The MMS spacecraft are spin stabilized, turning at a rate of three revolutions per minute to maintain orientation. Each spacecraft contains 12 thrusters connected to four hydrazine fuel tanks. Position data is provided by highly sensitive GPS equipment, while attitude is maintained by four star trackers, two accelerometers, and two Sun sensors.

The mission is broken into three phases. The commissioning phase will last approximately five and a half months after launch, while the science phases will last two years. The first science phase will focus on the magnetic boundary between the Earth and Sun (day side operations) for one and a half years, with the spacecraft formation orbiting the Earth at {{cvt|2550|by|70080|km}}. The second science phase will study reconnection in Earth's magnetic tail (night side operations) for half a year, increasing the orbit to {{cvt|2550|by|152900|km}}.

File:Magnetospheric Multiscale Mission 008 cg lg.jpg

Each spacecraft carries several experiments, divided into three suites: the Hot Plasma Suite, the Energetic Particles Detector Suite, and the Fields Suite.{{cite web |url=https://www.nasa.gov/mission_pages/mms/spacecraft/mms-instruments.html|title=Instruments Aboard MMS|publisher=NASA|date=30 July 2015|access-date=2 January 2016}} {{PD-notice}}

The Hot Plasma Suite measures plasma particle counts, directions, and energies during reconnection. It consists of two instruments:

• Fast Plasma Investigation (FPI), a set of four dual electron spectrometers (DES) and four dual ion spectrometers (DIS).{{Cite journal |last1=Pollock |first1=C. |last2=Moore |first2=T. |last3=Jacques |first3=A. |last4=Burch |first4=J. |last5=Gliese |first5=U. |last6=Saito |first6=Y. |last7=Omoto |first7=T. |last8=Avanov |first8=L. |last9=Barrie |first9=A. |last10=Coffey |first10=V. |last11=Dorelli |first11=J. |last12=Gershman |first12=D. |last13=Giles |first13=B. |last14=Rosnack |first14=T. |last15=Salo |first15=C. |date=2016-03-01 |title=Fast Plasma Investigation for Magnetospheric Multiscale |url=https://doi.org/10.1007/s11214-016-0245-4 |journal=Space Science Reviews |language=en |volume=199 |issue=1 |pages=331–406 |doi=10.1007/s11214-016-0245-4 |bibcode=2016SSRv..199..331P |s2cid=255065646 |issn=1572-9672|doi-access=free }}
• Hot Plasma Composition Analyzer (HPCA), detects particle speed in order to determine its mass and type.

The Energetic Particles Detector Suite detects particles at energies far exceeding those detected by the Hot Plasma Suite. It consists of two instruments:

• Fly's Eye Energetic Particle Sensor (FEEPS), a set of silicon solid state detectors to measure electron energy. Between two FEEPS per spacecraft, the individual detectors are arranged to provide 18 different view angles simultaneously; hence the term "fly's eye".

• Energetic Ion Spectrometer (EIS), measures energy and total velocity of detected ions in order to determine their mass. The EIS can detect helium and oxygen ions at energies higher than that of the HPCA.

The Fields Suite{{Cite journal |last=Torbert |first=R. B. |last2=Russell |first2=C. T. |last3=Magnes |first3=W. |last4=Ergun |first4=R. E. |last5=Lindqvist |first5=P.-A. |last6=LeContel |first6=O. |last7=Vaith |first7=H. |last8=Macri |first8=J. |last9=Myers |first9=S. |last10=Rau |first10=D. |last11=Needell |first11=J. |last12=King |first12=B. |last13=Granoff |first13=M. |last14=Chutter |first14=M. |last15=Dors |first15=I. |date=2016-03-01 |title=The FIELDS Instrument Suite on MMS: Scientific Objectives, Measurements, and Data Products |url=https://doi.org/10.1007/s11214-014-0109-8 |journal=Space Science Reviews |language=en |volume=199 |issue=1 |pages=105–135 |doi=10.1007/s11214-014-0109-8 |issn=1572-9672|doi-access=free }} measures magnetic and electric field characteristics. It consists of six instruments:

• Analog Fluxgate magnetometer (AFG), determines the strength of magnetic fields.
• Digital Fluxgate magnetometer (DFG), determines the strength of magnetic fields.
• Electron Drift Instrument (EDI), measures electric and magnetic field strength by sending a beam of electrons into space and measuring how long it takes the electrons to circle back in the presence of these fields.
• Spin-plane Double Probe (SDP),{{Cite journal |last1=Lindqvist |first1=P.-A. |last2=Olsson |first2=G. |last3=Torbert |first3=R. B. |last4=King |first4=B. |last5=Granoff |first5=M. |last6=Rau |first6=D. |last7=Needell |first7=G. |last8=Turco |first8=S. |last9=Dors |first9=I. |last10=Beckman |first10=P. |last11=Macri |first11=J. |last12=Frost |first12=C. |last13=Salwen |first13=J. |last14=Eriksson |first14=A. |last15=Åhlén |first15=L. |date=2016-03-01 |title=The Spin-Plane Double Probe Electric Field Instrument for MMS |url=https://doi.org/10.1007/s11214-014-0116-9 |journal=Space Science Reviews |language=en |volume=199 |issue=1 |pages=137–165 |doi=10.1007/s11214-014-0116-9 |bibcode=2016SSRv..199..137L |s2cid=255069089 |issn=1572-9672|doi-access=free }} consists of electrodes on the end of four {{cvt|60|m}} wire booms that extend from the spacecraft to measure electric fields.
• Axial Double Probe (ADP),{{Cite journal |last1=Ergun |first1=R. E. |last2=Tucker |first2=S. |last3=Westfall |first3=J. |last4=Goodrich |first4=K. A. |last5=Malaspina |first5=D. M. |last6=Summers |first6=D. |last7=Wallace |first7=J. |last8=Karlsson |first8=M. |last9=Mack |first9=J. |last10=Brennan |first10=N. |last11=Pyke |first11=B. |last12=Withnell |first12=P. |last13=Torbert |first13=R. |last14=Macri |first14=J. |last15=Rau |first15=D. |date=2016-03-01 |title=The Axial Double Probe and Fields Signal Processing for the MMS Mission |url=https://doi.org/10.1007/s11214-014-0115-x |journal=Space Science Reviews |language=en |volume=199 |issue=1 |pages=167–188 |doi=10.1007/s11214-014-0115-x |bibcode=2016SSRv..199..167E |s2cid=255071960 |issn=1572-9672|doi-access=free }} a set of electrodes on two {{cvt|15|m}} antennas mounted axially on the spacecraft.
• Search Coil Magnetometer (SCM), an induction magnetometer used to measure magnetic fields.

File:Atlas V MMS 2015-03-15 NASA.jpg

File:NASA Spacecraft Finds New Magnetic Process in Turbulent Space.webm

The principal investigator is James L. Burch of Southwest Research Institute, assisted by an international team of investigators, both instrument leads and theory and modeling experts.{{cite web|url=http://mms.space.swri.edu/team.html|title=The SMART Team|publisher=Southwest Research Institute|access-date=28 September 2012|archive-date=10 October 2008|archive-url=https://web.archive.org/web/20081010202640/http://mms.space.swri.edu/team.html|url-status=dead}} The project scientist is Thomas E. Moore of Goddard Space Flight Center.{{cite web|url=http://www.nasa.gov/topics/solarsystem/sunearthsystem/main/tmoore-qanda.html|title=Q&A: Missions, Meetings, and the Radial Tire Model of the Magnetosphere|publisher=NASA |first1=Karen C.|last1=Fox|first2=Tom|last2=Moore|date=1 October 2010|access-date=28 September 2012}} {{PD-notice}} Education and public outreach is a key aspect of the mission, with student activities, data sonification, and planetarium shows being developed.

The mission was selected for support by NASA in 2005. System engineering, spacecraft bus design, integration and testing has been performed by Goddard Space Flight Center in Maryland. Instrumentation is being improved, with extensive experience brought in from other projects, such as the IMAGE, Cluster and Cassini missions. In June 2009, MMS was allowed to proceed to Phase C, having passed a Preliminary Design Review. The mission passed its Critical Design Review in September 2010.{{cite news |url=http://www.nasa.gov/topics/solarsystem/sunearthsystem/main/mms-cdr.html|title=NASA's Magnetospheric Mission Passes Major Milestone|publisher=NASA|first=Susan|last=Hendrix|date=3 September 2010|access-date=28 September 2012}} {{PD-notice}} The spacecraft launched on an Atlas V 421 launch vehicle,{{cite press release|url=http://www.ulalaunch.com/site/pages/News.shtml#/26|title=United Launch Alliance Atlas V Awarded Four NASA Rocket Launch Missions|publisher=United Launch Alliance|date=16 March 2009|access-date=5 August 2009|archive-url=https://web.archive.org/web/20150720000149/http://www.ulalaunch.com/site/pages/News.shtml#/26|archive-date=20 July 2015|url-status=dead}} in March 2015.{{cite news|url=http://www.spacenews.com/article/spending-lags-growing-recognition-heliophysics-contribution|title=Spending Lags Growing Recognition of Heliophysics' Contribution|publisher=SpaceNews|first=Debra |last=Werner|date=19 December 2011|access-date=6 March 2014}}

In order to collect the desired science data, the four satellite MMS constellation must maintain a tetrahedral formation through a defined region of interest in a highly elliptical orbit. The formation is maintained through the use of a high altitude rated GPS receiver, Navigator, to provide orbit knowledge, and regular formation maintenance maneuvers.{{cite web|url=https://mms.gsfc.nasa.gov/spacecraft.html|title=Magnetospheric Multiscale Spacecraft|work=Goddard Space Flight Center|publisher=NASA|access-date=1 May 2018}} {{PD-notice}} Through Navigator, the MMS mission broke the Guinness World Record twice for highest altitude fix of a GPS signal (at {{cvt|70000|km}} and {{cvt|187200|km}} above the surface in 2016 and 2019 respectively).{{cite web|last=Johnson-Groh|first=Mara|url=https://www.nasa.gov/feature/goddard/2016/nasa-s-mms-breaks-guinness-world-record|title=NASA's MMS Breaks Guinness World Record|publisher=NASA |date=4 November 2016|access-date=12 March 2020}} {{PD-notice}}{{cite web|last=Baird|first=Danny|url=https://www.nasa.gov/feature/goddard/2019/record-breaking-satellite-advances-nasa-s-exploration-of-high-altitude-gps|title=Record-Breaking Satellite Advances NASA's Exploration of High-Altitude GPS|publisher=NASA|date=4 April 2019|access-date=12 March 2020}} {{PD-notice}}

In 2016, the MMS mission was the first to directly detect magnetic reconnection, the phenomenon which drives space weather in the Earth's magnetosphere.{{cite web |url=http://www.scientificamerican.com/article/nasa-probes-witness-powerful-magnetic-storms-near-earth/|title=NASA Probes Witness Powerful Magnetic Storms near Earth|publisher=Scientific American|first=Charles Q.|last=Choi|date=13 May 2016|access-date=14 May 2016}}{{cite journal|doi=10.1126/science.aaf2939|pmid=27174677|bibcode=2016Sci...352.2939B|title=Electron-scale measurements of magnetic reconnection in space|journal=Science |volume=352|issue=6290|at=aaf2939|date=June 2016|last1=Burch|first1=J. L.|last2=Torbert|first2=R. B.|last3=Phan|first3=T. D.|last4=Chen|first4=L.-J.|last5=Moore|first5=T. E. |last6=Ergun|first6=R. E.|last7=Eastwood|first7=J. P.|last8=Gershman|first8=D. J.|last9=Cassak|first9=P. A.|last10=Argall|first10=M. R.|last11=Wang|first11=S.|last12=Hesse|first12=M.|last13=Pollock|first13=C. J.|last14=Giles|first14=B. L.|last15=Nakamura|first15=R.|last16=Mauk|first16=B. H.|last17=Fuselier|first17=S. A.|last18=Russell|first18=C. T.|last19=Strangeway|first19=R. J.|last20=Drake|first20=J. F. |last21=Shay|first21=M. A.|last22=Khotyaintsev|first22=Yu. V.|last23=Lindqvist|first23=P.-A.|last24=Marklund|first24=G.|last25=Wilder|first25=F. D.|last26=Young|first26=D. T.|last27=Torkar|first27=K. |last28=Goldstein|first28=J.|last29=Dorelli|first29=J. C.|last30=Avanov|first30=L. A.|display-authors=1|hdl=10044/1/32763|doi-access=free|hdl-access=free}}

MMS has since detected magnetic reconnection occurring in unexpected places. In 2018, MMS made the first-ever detection of magnetic reconnection in the magnetosheath, a region of space previously thought to be too chaotic and unstable to sustain reconnection.{{cite web|last=Johnson-Groh|first=Mara|url=https://www.nasa.gov/feature/goddard/2018/nasa-spacecraft-discovers-new-magnetic-process-in-turbulent-space |title=NASA Spacecraft Discovers New Magnetic Process in Turbulent Space|publisher=NASA|date=9 May 2018|access-date=12 March 2020}} {{PD-notice}} Magnetic flux ropes and Kelvin–Helmholtz vortices are other phenomena where MMS has detected reconnection events against expectations.

In August 2019, astronomers reported that MMS made the first high-resolution measurements of an interplanetary shock wave from the Sun.{{cite web|url=https://www.nasa.gov/feature/goddard/2019/nasa-s-mms-finds-first-interplanetary-shock|title=NASA's MMS Finds Its 1st Interplanetary Shock|last=Johnson-Groh|first=Mara|publisher=NASA|date=8 August 2019|access-date=12 August 2019}} {{PD-notice}}

{{Portal|Spaceflight}}

• IMAGE, the Imager for Magnetopause-to-Aurora Global Exploration, a prior magnetosphere research satellite
• PUNCH
• TRACERS

{{reflist|refs=

{{cite web|url=https://www.nasa.gov/sites/default/files/files/MMS_PressKit.pdf|title=Magnetospheric Multiscale: Using Earth's magnetosphere as a laboratory to study the microphysics of magnetic reconnection|publisher=NASA|date=March 2015|access-date=12 March 2015}}

}}

{{refbegin}}

• {{cite book|title=An Introduction to Space Weather|publisher=Cambridge University Press|first=Mark|last=Moldwin|year=2008|isbn=978-0-521-86149-6}}
• {{cite news|url=http://www.spacedaily.com/news/earth-magnetic-05f.html|title=SwRI To Lead NASA's Magnetospheric Multiscale Mission|publisher=Space Daily|date=12 May 2005}}
• {{cite book|chapter=Magnetospheric Multiscale Mission|title=Nonequilibrium Phenomena in Plasmas|publisher=Springer Netherlands|series=Astrophysics and Space Science Library|first1=A. Surjalal|last1=Sharma |first2=Steven A.|last2=Curtis|volume=321|pages=179–195|year=2005|isbn=978-1-4020-3108-3|doi=10.1007/1-4020-3109-2_8}}
• {{cite book|title=The Sun to the Earth - And Beyond|publisher=National Academies Press|author=National Research Council|year=2003|isbn=978-0-309-08972-2}}
• {{cite book|url=http://purl.access.gpo.gov/GPO/LPS70969|title=2006 NASA Strategic Plan|publisher=NASA|year=2006|id=NP-2006-02-423-HQ|oclc=70110760}}
• {{cite book|url=http://science1.nasa.gov/media/medialibrary/2010/03/31/Science_Plan_07.pdf|title=Science Plan for NASA's Science Mission Directorate 2007–2016|publisher=NASA|year=2007|id=NP-2007-03-462-HQ |url-status=dead|archive-url=https://web.archive.org/web/20140224082547/http://science1.nasa.gov/media/medialibrary/2010/03/31/Science_Plan_07.pdf|archive-date=24 February 2014}}

{{refend}}

{{commons category|Magnetospheric Multiscale Mission}}

• [https://mms.gsfc.nasa.gov/ Magnetospheric Multiscale Mission site] by NASA's Goddard Space Flight Center
• [https://science.nasa.gov/mission/mms Magnetospheric Multiscale Mission site] by NASA's Mission Directorate
• [https://mms.space.swri.edu/ Magnetospheric Multiscale Mission site] by Southwest Research Institute
• [https://mms.rice.edu Magnetospheric Multiscale Mission site] by Rice University
• {{YouTube|user=nasamms|Magnetospheric Multiscale Mission}}

{{NASA space program}}

{{Magnetosphere}}

{{Orbital launches in 2015}}

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