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Magnetic Wave Fields

NSSDCA ID: 1977-029A-06

Mission Name: ESA-GEOS 1
Principal Investigator:Dr. Roger E. Gendrin


The instrument (part of ESA Exp. S-300) used two sets of three-axis search coil magnetometers, one for the ULF/ELF range (0.1 to 450 Hz) and one for the VLF range (0.3 to 30 kHz). Each search coil consisted of a high-permeability material with a high density pick-up winding. Each set of the three coils was built into a single assembly and mounted on the locking 3-m booms at a distance of 2 m from the spacecraft. Typical sensitivities of these sensors in units of nT per sq root of Hz were 1.0E-1 at 0.1 Hz, 2.0E-4 at 10 Hz, and about 3.0E-6 at 1 kHz. These sensors and some associated electronics consisting of (1) a large number of channel-selection switches, (2) a number of bandpass filters, (3) six swept-frequency analyzers (SFA), (4) a digital correlator, and (5) eight stepped-gain amplifiers, comprise part of the ESA wave experiment S-300. These components were employed for the sensors described in 77-029A-07 (Pedersen) and 77-029A-10 (Ungstrup), and also the investigations described in 77-029A-05 (Petit) and 77-029A-11 (Beghin). Six analog channels of 450 Hz bandwidth and the digital correlator output were transmitted via the 95.25 kbs telemetry mode. The SFA covered the frequency range up to 77 kHz in 256 partly overlapping steps. The correlator provided an auto-correlogram of 128 points within 29 ms. Its bandwidth could be selected to be 2.5, 5.0, or 10.0 kHz. Cross-correlograms between two sensors could be provided. The correlator could also operate in a time-sharing mode between auto-correlation and cross-correlation.

Alternate Names

  • ESA-GEOS1/MagneticWaveFields
  • S300
  • S325
  • S326

Funding Agency

  • European Space Agency (International)


  • Space Physics: Magnetospheric Studies

Additional Information

Questions and comments about this experiment can be directed to: Coordinated Request and User Support Office



NameRoleOriginal AffiliationE-mail
Dr. Eigil UngstrupOther InvestigatorDanish Space Research
Dr. Jacquelyne M. EtchetoOther InvestigatorCentre National d'Etudes des
Dr. Roger E. GendrinPrincipal InvestigatorCentre National d'Etudes des Telecommunications
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