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TWINS A & B mission graphic

Two Wide-Angle Imaging Neutral-Atom Spectrometers

Phase: Operating

Launch Date: March 13, 2008

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Program(s):Explorers, Heliophysics Explorers, Heliophysics Research, Missions of Opportunity

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The Two Wide-angle Imaging Neutral-atom Spectrometers missions, TWINS-A and TWINS-B, provide a new capability for stereoscopically imaging the magnetosphere. By imaging the charge exchange neutral atoms over a broad energy range (~1-100 keV) using two identical instruments on two widely spaced high-altitude, high-inclination spacecraft, TWINS will enable the 3-dimensional visualization and the resolution of large scale structures and dynamics within the magnetosphere for the first time. In contrast to traditional space experiments, which make measurements at only one point in space, imaging experiments provide simultaneous viewing of different regions of the magnetosphere. Stereo imaging, as done by TWINS, takes the next step of producing 3-D images, and will provide a leap ahead in our understanding of the global aspects of the terrestrial magnetosphere.

The TWINS instrumentation is essentially the same as the MENA instrument on the IMAGE mission. This instrumentation consists of a neutral atom imager covering the ~1-100 keV energy range with 4°x4° angular resolution and 1-minute time resolution, and a simple Lyman-alpha imager to monitor the geocorona.

TWINS will provide stereo imaging of the Earth's magnetosphere, the region surrounding the planet controlled by its magnetic field and containing the Van Allen radiation belts and other energetic charged particles. TWINS will enable three-dimensional global visualization of this region, which will lead to greatly enhanced understanding of the connections between different regions of the magnetosphere and their relation to the solar wind.