Calibration of Doppler measurements by the Giotto comet probe using the nutation of the spacecraft
Abstract
The Giotto spacecraft experienced a slight deceleration during its flyby at Comet Halley. Two-way Doppler and ranging measurements before and after the flyby on the one hand, and one-way Doppler measurements during the flight through the cometary atmosphere on the other, both taken on the X-band downlink, yielded different values of this deceleration. In this paper, the Doppler shift expected from the nutational motion of the spacecraft is simulated using calculated amplitude and phase diagrams of the Giotto High Gain Antenna, and the results indicate that part of the one-way Doppler shift can be attributed to oscillator drift due to interaction with the cometary atmosphere. Thus, the deceleration was partly simulated.
- Publication:
-
Kleinheubacher Berichte
- Pub Date:
- 1990
- Bibcode:
- 1990KlBer..33..189H
- Keywords:
-
- Doppler Effect;
- Flyby Missions;
- Giotto Mission;
- Halley'S Comet;
- Instrument Compensation;
- Nutation;
- Calibrating;
- Cometary Atmospheres;
- Downlinking;
- Astrodynamics