The NASA Advanced Composition Explorer (ACE, launched 1997) measures magnetic fields and particles of the solar wind at the L1 first Lagrangian point at about 220 Re upstream of the Earth. As typical speeds vary between 350-1000 km/s, it takes anywhere from about 20 to 70 min before the measured solar wind impacts the Earth’s magnetosphere. The ACE spacecraft provides real-time solar wind and interplanetary magnetic field observations for space weather forecasting purposes.
The NASA Wind (launched 1994) spacecraft measures radio waves and plasma in the solar wind and in the magnetosphere. Since 2004, the satellite has been located at the L1 point and thus provides continuous monitoring of the solar wind and interplanetary magnetic field. Before 2004, Wind had a variable orbit which at times crossed the magnetosphere.
The NASA 5-spacecraft Time History of Events and Macroscale Interactions during Substorms (THEMIS, launched 2007) constellation mission was set to study the instabilities related to space weather disturbances such as substorms. The spacecraft were originally set to orbits with apogee at 10, 12 (two probes), 20 and 30 Re to record the substorm evolution along the magnetotail, while providing information about processes at the magnetospheric boundaries when the apogee are on the dayside. The orbital configurations have since been changed, and now three of the probes have their apogee at 13 Re, while the two outer probes were moved further out to orbit the Moon monitoring the magnetotail at 60 Re distance.
The NASA Magnetospheric Multiscale Mission (MMS, launched 2015) with its four closely spaced craft in a tetrahedral configuration focuses on plasma microphysics, especially the physics of magnetic reconnection, energetic particle acceleration, and turbulence.
The two NASA Van Allen Probes (VAP, 2012-2019), also known as the Radiation Belt Storm Probes (RBSP), were designed to study the detailed plasma and energetic particle processes in the Van Allen radiation belts in the inner magnetosphere.
GEOTAIL (launched 1992) is a Japan – US collaboration magnetospheric spacecraft that has had multiple orbits covering the magnetosphere from the near-magnetotail to the very distant magnetotail. Geotail measures the magnetic fields and particles to study the global magnetospheric dynamics.
CLUSTER (launched 2000) is an European Space Agency four-spacecraft mission to study especially the high-latitude magnetospheric processes, especially near the dayside cusp regions. The Cluster craft have a comprehensive instrumentation covering the electromagnetic fields and plasmas from low to high energies.
More information about missions CLaSP is or has been part of can be found here.
