The Inner Magnetosphere Explorer (IMEX) was selected as one of the first missions of
the NASA University-Class Explorers Program.
The principal investigator is
Professor John R. Wygant of the University of Minnesota.
- IMEX is scheduled for launch in mid-2001, just after the peak of solar cycle 23.
Its mission is to study the dynamics of the inner magnetosphere during major
geomagnetic storms. It will be the first mission in the inner magnetosphere to
contain a full complement of field and particle detectors (especially electric
fields) while there is a full-time upstream monitor in the solar wind
(the ACE mission).
- The mission and orbit are patterned after
mission - the orbit will be a low-inclination GTO (~10 hour period), and the apogee of
IMEX's orbit will precess through all local times over a 17 month period.
The spacecraft spin axis will point towards the sun to provide
constant illumination to the solar panels and to provide uniform
illumination of the electric field antennas to reduce
spurious signals due to varying amounts of photo-electron emission.
- The mission will benefit by collaborative data analysis with the IMAGE
and TWINS missions. These missions are designed to provide global imaging of
the aurora, ring current, and plasmaspheric populations. IMEX will provide in
situ measurements (particularly of electric fields and ring current populations)
and cross-calibration, while TWINS and IMAGE will provide a context for
interpreting the IMEX measurements.
- Science section of the IMEX proposal
- Mission Implementation section of the IMEX proposal (section G)
Spacecraft Instruments and Information
(for more information check out the science section of the IMEX proposal)
FIELDS - University of Minnesota
- double probe instrument measures DC to 20 Hz electric fields between .05-500 mV/m
- samples up to 40 kHz electric fields in burst mode between .01-100 mV/m
- search coils measure 1pT to 3nT magnetic fields in burst mode between 100 Hz and 20 kHz
- Langmuir probe mode measures plasma density and temperature with
5 minute resolution
(in addition to spacecraft potential measurements
which measure thermal electron flux with 0.5 s resolution)
Fluxgate Magnetometer - Goddard Space Flight Center
- provides up to 20 Hz magnetic field
measurements from .016-64000 nT
HEPEX (High Energy Particle Experiment) - Aerospace Corporation
Ring Current Ion Sensor (RIS)
- Magnetic spectrograph
- measures 2D distributions of 30-500 keV hydrogen and 50-500 keV oxygen
(also some measurements of helium) with 3 s resolution
Energetic Electron Spectrograph (EES)
- Magnetic spectrograph
- measures 2D distributions of 10 keV to 1.5 MeV electrons with 3 s resolution
Relativistic Electron Detectors (RED)
- Set of 5 threshold sensors
- measures omnidirectional flux of 2-15 MeV electrons (1 s resolution)
- measures omnidirectional flux of 20-100 MeV protons (1 s resolution)
3-D LEPA - UC Berkeley
- Electrostatic analyzers
- Measures 3D distributions of ~3 eV to 30 keV electrons and ions
with spin period (~6 s) resolution
This is the latest concept for the design of the IMEX spacecraft (3/24/99).
The view shown here is the dark side of the spacecraft. The solar panels are on the sunlit side "underneath".
For more images, including a view of IMEX piggybacking on the Inertial Upper Stage, go here.
News Coverage of the IMEX Mission
"U scientists design satellite to
Study Van Allen Belts" by Jim Dawson, Minneapolis Star Tribune,
Wednesday October 14, 1998
"Newton's Apple: The Magnetosphere" by Mark Ward, Minneapolis Star Tribune,
Wednesday, October 14, 1998
"Final Frontier is U's New Baby" by Jake Kapsner, Minnesota Daily, September 21, 1998
"2001 Space Mission: Into The Heart Of The Van Allen
Belts," ScienceDaily, September 17, 1998
"NASA gives U $13 million to design craft" by Judith Yates Borger, St. Paul Pioneer Press,
September 16, 1998 - Available from the
Pioneer Press News Archives
"U gets $13 million to build magnetosphere satellite" by Jim Dawson, Minneapolis Star Tribune,
Metro/Region Section, September 16, 1998 - Available from the
Star Tribune Archives
NASA Press Release, September 11, 1998
Other IMEX Websites:
Magnetospheric Physics on the WWW:
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Last Updated : Feb 25, 1999
This page is maintained by Doug Rowland.