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Energetic Ion Mass Spectrometer (0-17 keV/q; 1 AMU to > 150 AMU)

NSSDCA ID: 1977-102A-12

Mission Name: ISEE 1
Principal Investigator:Dr. O. Walter Lennartsson


The objective of this investigation was to determine the ion composition and energy spectra of the plasma within the magnetosphere, magnetosheath, and solar wind, and to determine the angular distribution of the plasma in the magnetosheath. An energetic ion mass spectrometer was flown that had an electrostatic energy analyzer followed by a combined cylindrical electrostatic/magnetic mass analyzer. A combination of electron multipliers was used as the detector. The energy-per-unit-charge range measured was from 0 to 17 keV/Q. The mass-per-unit-charge range measured extended from 1 to 150 u/Q.

Alternate Names

  • ISEE1/EnergeticIonMassSpectrometer

Facts in Brief

Mass: 10.6 kg
Power (avg): 8.5 W

Funding Agency

  • NASA-Office of Space Science (United States)


  • Space Physics: Magnetospheric Studies
  • Space Physics: Heliospheric Studies

Additional Information

Questions and comments about this experiment can be directed to: Dr. H. Kent Hills



NameRoleOriginal AffiliationE-mail
Dr. Helmut R. RosenbauerOther InvestigatorMax-Planck-Institut fur
Dr. Gerhard HaerendelOther InvestigatorMax-Planck-Institut fur Extraterrestrische
Prof. Peter X. EberhardtOther InvestigatorUniversitat
Dr. Richard G. JohnsonOther InvestigatorOffice of Science and Technology Policy
Prof. Johannes GeissOther InvestigatorUniversitat
Dr. David T. YoungOther InvestigatorLos Alamos National
Dr. Charles R. ChappellOther InvestigatorNASA Marshall Space Flight
Prof. Hans R. BalsigerOther InvestigatorUniversitat
Dr. Edward G. ShelleyOther InvestigatorLockheed Palo
Dr. Arthur G. GhielmettiOther InvestigatorUniversitat
Dr. O. Walter LennartssonPrincipal InvestigatorLockheed Palo

Selected References

  • Shelley, E. G., et al., Plasma composition experiment on ISEE-A, IEEE Trans. Geosci. Electron., GE-16, No. 3, 266-270, doi:10.1109/TGE.1978.294560, July 1978.
  • Lennartsson, W., et al., Some initial ISEE 1 results on the ring current composition and dynamics during the magnetic storm of December 11, 1977, Geophys. Res. Lett., 6, No. 6, 483-486, doi:10.1029/GL006i006p00483, June 1979.
  • Lennartsson, W., et al., Ion composition and energy distribution during 10 magnetic storms, J. Geophys. Res., 86, No. A6, 4628-4638, doi:10.1029/JA086iA06p04628, June 1981.
  • Sharp, R. D., et al., Hot plasma composition results from the ISEE-1 spacecraft, in Energetic Ion Composition in the Earth's Magnetosphere, 231-261, R.G. Johnson, Center for Acad. Publ., Tokyo, Japan, doi:10.007/978-94-009-7105-9_9, 1983.
  • Lennartson, W., International Sun-Earth Explorer (ISEE-1) plasma composition experiment data reduction and analysis, Lockheed Missiles and Space Company, Inc., Res. and Dev., Palo Alto, CA, Final Report, Dec. 1989.
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