Doppler and ranging measurements using the radio signal of the Giotto spacecraft were taken before, during, and after the encounter with Comet Halley on Mar. 13, 14, 1986. The spacecraft velocity was found to decrease by a total of 23.3 cm/s due to impacting gas and (primarily) dust in the cometary atmosphere. A preliminary dust production rate of 1000 kg/s is found to be consistent with this deceleration. Power spectra of the carrier phase fluctuations reveal an increase in level and a flattening of the spectrum just prior to encounter, presumably associated with the enhanced dust impact rate. Finally, simulated Doppler time profiles are computed using the radial dependence of plasma density observed by the Giotto in situ investigations. It is shown that the cometary electron content profile would have been clearly seen if a dual-frequency downlink radio configuration had been available at encounter.
Preliminary results of the Giotto radio science experiment
Advances in Space Research ; 5 , 12, 1
1985-01-01
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Preliminary results of the Giotto radio science experiment
Elsevier | 1985
|Measurement technique for the Giotto radio science experiment
Tema Archiv | 1987
|The Giotto magnetometer experiment
Tema Archiv | 1987
|The Giotto electron plasma experiment
Tema Archiv | 1987
|GIOTTO: AN HISTORICAL PERSPECTIVE - The Giotto Spacecraft plus "Why was Giotto Special?"
Online Contents | 2002
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