NSSDCA ID: 1976-003A-04
Mission Name: Helios-BThis experiment (E5a) shared the 32-m, tip-to-tip, electric antenna with experiments -05 and -06. The instrument consisted of a 16-channel spectrum analyzer with approximately logarithmically equispaced center frequencies, 16 log compressors, 16 R-C integrators for averaging the log-compressed, electric field amplitude between readouts, and 16 peak detectors which were reset after readout. The 16 averages and 16 peak log values were sampled almost simultaneously. The channels covered the frequency range of about 20 Hz to 200 kHz, with four channels per decade of frequency. The log compressors had a dynamic range of 100 dB. Sampling rate depended in detail on the spacecraft bit rate and telemetry format. The fastest real-time telemetered rate was for 16 averages and 16 peak values to be sampled every 1.125 s. Whenever a very strong signal was detected in a pre-selected channel, the shock alarm data mode was initiated in which the electric field spectrum, magnetic field, and plasma data were recorded into spacecraft memory for a period starting before and terminating after the triggering signal time. The maximum sampling rate of the spectrum data in this mode was 14.2 samples per s for each channel. Interference, caused by solar cell noise, occurred primarily in the lowest six channels, and harmonics were related to the spin frequency and the spacecraft sheath. However, a combination of factors, including the proper deployment of the dipole antenna and the conductive spacecraft coating, resulted in data from this spacecraft being of higher quality than data from Helios-A. For further details, see pp. 245-247 of Raumfahrtforschung, v. 19, n. 5, 1975.
Questions and comments about this experiment can be directed to: Dr. H. Kent Hills
Name | Role | Original Affiliation | |
---|---|---|---|
Dr. Robert G. Stone | Other Investigator | NASA Goddard Space Flight Center | stone@urap.gsfc.nasa.gov |
Dr. Paul J. Kellogg | Other Investigator | University of Minnesota | kellogg@waves.space.umn.edu |
Dr. Siegfried J. Bauer | Other Investigator | Universitat Graz, Austria | |
Prof. Donald A. Gurnett | Principal Investigator | University of Iowa |