THEMIS (Time History of Events and Macroscale Interactions during Substorms) was launched in 2007 as five identical satellites for measuring the magnetic and plasma environment around Earth. After completing their prime mission, two THEMIS satellites were maneuvered into orbit around the Moon to study the lunar enviroment in a mission known as THEMIS-ARTEMIS.

THEMIS & ARTEMIS mission page @ NASA

THEMIS & ARTEMIS mission page @ UC/Berkeley

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THEMIS Science

Visualizations & animations related to THEMIS science results.
  • NASA Spacecraft Uncover Mystery Behind Auroral Beads
    A special type of aurora, draped east-west across the night sky like a glowing pearl necklace, is helping scientists better understand the science of auroras and their powerful drivers out in space. Known as auroral beads, these lights often show up just before large auroral displays, which are caused by electrical storms in space called substorms. Until now, scientists weren’t sure if auroral beads are somehow connected to other auroral displays as a phenomenon in space that precedes substorms, or if they are caused by disturbances closer to Earth’s atmosphere.
  • NASA Observes Auroras Across Canada
    The dancing lights in the video are the aurora borealis or Northern Lights. These auroras are at their most dynamic during geomagnetic storms—often the result of solar storms called coronal mass ejections, or CMEs, that originate from the sun. The aurora shown above occurred as the result of a CME that erupted from the sun early on Mar. 15, 2013. Some 46 hours later, early on Mar. 17, 2013, this CME struck Earth’s magnetic field, depositing and storing energy in Earth’s magnetosphere. When this energy was released, charged particles from the magnetosphere were sent rushing down towards Earth’s atmosphere where they collided with neutral particles, creating the brilliant aurora.
  • Several NASA Spacecraft Track Energy Through Space
    Taking advantage of an unprecedented alignment of eight satellites through the vast magnetic environment that surrounds Earth in space, including NASA's ARTEMIS and THEMIS, scientists now have comprehensive details of the energy's journey through a process that forms the aurora, called a substorm.
  • Reconnection Fronts - What the Models Say...
    Mathematical models of Earth's magnetosphere have become increasingly more complex and accurate. They have sufficient detail to illustrate many small-scale phenomena.
  • Reconnection Fronts - When Satellites Align...
    In July of 2012, a fleet of spacecraft studying Earth's magnetosphere were in an ideal alignment to detect a particle flow predicted in magnetospheric models. The grey mesh shell structure represents the approximate location of the magnetopause.

    In this visualization, THEMIS, ARTEMIS (in orbit around the Moon), and Geotail, as well as the particle detectors on the GOES-13 and GOES-15 satellites achieved a good alignment around 09:45 on July 3, 2012 to detect one of the particle flows predicted by magnetospheric models.

  • Rebounding Plasma Flows in the Inner Magnetosphere
    Substorms send jets of plasma careening Earthward at speeds near 600,000 miles/hour. Researchers comparing multipoint THEMIS spacecraft observations with the predictions of numerical simulations have determined the width of one such jet and determined what happened to it when it encountered the strong magnetic fields within the inner magnetosphere. Plasma jets with the width of the Earth slam into the inner magnetosphere, generating vortices with opposite senses of rotation that appear and disappear on either side of the plasma jet.
  • THEMIS/ASI Nights - High Resolution
    A collection of ground-based All-Sky Imagers (ASI) makes an important component of the THEMIS mission in understanding the interaction of the magnetosphere and aurora. It is sometimes referred to as the sixth THEMIS satellite.
  • THEMIS discovers biggest breach of Earth's solar storm shield
    The latest findings from the THEMIS mission: Earth's magnetic field, which shields our planet from severe space weather, often develops two holes ten times larger than anything previously though to exist, allowing solar particles in.

  • THEMIS Discovers Biggest Breach of Earth's Magnetosphere
    NASA's THEMIS mission has overturned a longstanding belief about the interaction between solar particles and Earth's protective magnetic field. This new discovery could help scientists predict when the solar storms that can disrupt power grids, satellites and even GPS signals, could be especially severe.
  • THEMIS Sees Magnetic Reconnection
    THEMIS observations confirm for the first time that magnetic reconnection in the magnetotail triggers the onset of substorms. Substorms are the sudden violent eruptions of space weather that release solar energy trapped in the Earth's magnetic field.
  • THEMIS Explores the Earth's Bow Shock
    The solar wind's first contact with the Earth's magnetic field creates a region known as the bow shock, much like the bow wave of a boat moving through the water. This region can also create additional turbulence which generates bursts of explosion-like currents.
  • THEMIS and the March 2007 Substorm
    NASA's Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission observed the dynamics of a rapidly developing substorm in March of 2007. This visualization combines the orbits of the THEMIS satellites with a magnetohydrodynamical simulation of the Earth's magnetosphere corresponding to this time.


THEMIS-ARTEMIS visualizations
  • ARTEMIS Mission
    An extension to the THEMIS mission is to send two of the THEMIS satellites into lunar orbit to study the magnetospheric environment near the Moon. The new mission is named ARTEMIS (Acceleration, Reconnection Turbulence, and Electrodynamics of Moon's Interaction with the Sun).
  • ARTEMIS at Lagrange
    This visualization is built from the components of ARTEMIS Mission with emphasis on the maneuvers of the two ARTEMIS spacecraft (red=ARTEMIS-1, green=ARTEMIS-2) around the lunar Lagrange Points L1 and L2.
  • ARTEMIS Orbits Magnetic Moon
    Launched in 2007, NASA's five THEMIS spacecraft have now successfully completed their 2 year mission to determine the cause of geomagnetic substorms. Because they are continuing to work perfectly, NASA is re-directing the outermost two spacecraft to special orbits at and around the Moon. This new mission, which is called ARTEMIS, uses some very complex maneuvers over two years (2009-2010) to get both spacecraft into position.
  • Magnetic Bubbles on the Moon...
    Much of the Moon's darker-colored 'mare' regions are considered to be older than the lighter-colored mountainous regions. Yet the maria contain a number of ligher-colored regions, such as Reiner Gamma. Why could that be? Many of these lighter regions in the maria appear to correspond to locations of magnetic anomalies which provides a hint for testing various hypotheses.
  • Magnetic Bubbles on the Moon Reveal Evidence of "Sunburn"
    Every object, planet or person traveling through space has to contend with the Sun's damaging radiation — and the Moon has the scars to prove it.

THEMIS Resources

Pre-launch and miscellaneous THEMIS resources.
  • Substorms
    This animation shows a magnetospheric substorm, during which the reconnection causes energy to be rapidly released along the field lines causing the auroras to brighten.
  • THEMIS ASI Ground Station Array
    This visualization shows the 20 THEMIS ASI ground station locations. These ground stations will assist the THEMIS satellite constellation in measuring the Aurora Borealis over North America. Each ground station has an all-sky imaging white-light auroral camera and a magnetometer. The ground stations' radial coverage is rendered at 540 km. An artist's conception of an aurora is added to the second part of the visualization for context.
  • THEMIS Launch and Deployment
    THEMIS (Time History of Events and Microscale Interactions durind Substorms) answers fundamental outstanding questions regarding the magnetospheric substorm instability, a dominant mechanism of transport and explosive release of solar wind energy within Geospace.
  • THEMIS Orbits: Transitions
    Between the dayside and nightside phases of the mission, the five spacecraft will conduct orbit change maneuvers over a period of three months. During this visualization, the camera position is locked in GSE coordinates, keeping the Sun to the left. The orbital axis is actually fixed in space but appears to move due to the Earth's motion around the Sun. The dates in this visualization are based on an ephemeris assuming a launch on January 20, 2007. The satellites are represented by the colors: red=P1, green=P2, cyan=P3, blue=P4, magenta=P5.
  • THEMIS Orbits: Nightside Science Configuration
    In the latter phase of the mission, the five THEMIS spacecraft will travel on five co-aligned elliptical orbits with their apogee on the nightside of the Earth. From there, they will sample the particle and electromagnetic wave environment along the magnetotail.
  • THEMIS Orbits: Dayside Science Configuration
    In the early part of the mission, the five THEMIS satellites will follow the same orbit single-file. The apogee of the orbit will take the spacecraft just beyond the bow shock of the Earth's magnetosphere. This will enable the satellites to collect data in this region over a short range of time so that the time history can be studied.
  • THEMIS Beauty Pass
    A closer look at one of the THEMIS spacecraft.
  • THEMIS Mission and Substorm Simulation
    This visualization combines simulations of the THEMIS (Time History of Events and Macroscale Interactions during Substorms) mission orbits with a GGCM (Geospace General Circulation Model) simulation. It illustrates how the five THEMIS satellites will work together to detect substorm events in the magnetosphere. One goal of the THEMIS mission is to test how these substorm events are related to the formation of the aurora.