Earth-based radio tracking of the Galileo probe for Jupiter wind estimation

Science

Volumn 275, Issue 5300, 1997, Pages 644-646

  Folkner, W M ^a   Preston, R A ^a   Border, J S ^a   Navarro, J ^b,d   Wilson, W E ^c   Oestreich, M ^c  

^a CALIFORNIA INSTITUTE OF TECHNOLOGY   (United States)

^b NATIONAL RADIO ASTRONOMY OBSERVATORY   (United States)

^c CSIRO   (Australia)

^d NONE   (Norway)

Author keywords

[No Author keywords available]

Indexed keywords

ARTICLE; ASTRONOMY; ATMOSPHERE; PRIORITY JOURNAL; SIGNAL DETECTION; SIGNAL NOISE RATIO; TELEMETRY;

EID: 0031053321     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.275.5300.644     Document Type: Article

References (30)

1. C. C. Counselman III, S. A. Gourevitch, R. W. King, G. B. Loriot, J. Geophys. Res. 85, 8026 (1980); V. V. Kerzhanovich and M. Ya. Marov, in Venus, M. Hunten et al., Eds. (Univ. of Arizona Press, Tucson, 1983), p. 766; R. A. Preston et al., Science 231, 1414 (1986); R. Z. Sagdeev et al., Astron. Astrophys. 254, 387 (1992).
2. C. C. Counselman III, S. A. Gourevitch, R. W. King, G. B. Loriot, J. Geophys. Res. 85, 8026 (1980); V. V. Kerzhanovich and M. Ya. Marov, in Venus, M. Hunten et al., Eds. (Univ. of Arizona Press, Tucson, 1983), p. 766; R. A. Preston et al., Science 231, 1414 (1986); R. Z. Sagdeev et al., Astron. Astrophys. 254, 387 (1992).
3. C. C. Counselman III, S. A. Gourevitch, R. W. King, G. B. Loriot, J. Geophys. Res. 85, 8026 (1980); V. V. Kerzhanovich and M. Ya. Marov, in Venus, M. Hunten et al., Eds. (Univ. of Arizona Press, Tucson, 1983), p. 766; R. A. Preston et al., Science 231, 1414 (1986); R. Z. Sagdeev et al., Astron. Astrophys. 254, 387 (1992).
4. C. C. Counselman III, S. A. Gourevitch, R. W. King, G. B. Loriot, J. Geophys. Res. 85, 8026 (1980); V. V. Kerzhanovich and M. Ya. Marov, in Venus, M. Hunten et al., Eds. (Univ. of Arizona Press, Tucson, 1983), p. 766; R. A. Preston et al., Science 231, 1414 (1986); R. Z. Sagdeev et al., Astron. Astrophys. 254, 387 (1992).
5. A. P. Ingersoll et al., J. Geophys. Res. 86, 8733 (1981); S. S. Limaye et al., J. Atmos. Sci. 39, 1413 (1982); S. S. Limaye, Icarus 65, 335 (1986); R. F. Beebe, A. A. Simon, L. F Huber, Science 272, 841 (1996).
6. A. P. Ingersoll et al., J. Geophys. Res. 86, 8733 (1981); S. S. Limaye et al., J. Atmos. Sci. 39, 1413 (1982); S. S. Limaye, Icarus 65, 335 (1986); R. F. Beebe, A. A. Simon, L. F Huber, Science 272, 841 (1996).
7. A. P. Ingersoll et al., J. Geophys. Res. 86, 8733 (1981); S. S. Limaye et al., J. Atmos. Sci. 39, 1413 (1982); S. S. Limaye, Icarus 65, 335 (1986); R. F. Beebe, A. A. Simon, L. F Huber, Science 272, 841 (1996).
8. A. P. Ingersoll et al., J. Geophys. Res. 86, 8733 (1981); S. S. Limaye et al., J. Atmos. Sci. 39, 1413 (1982); S. S. Limaye, Icarus 65, 335 (1986); R. F. Beebe, A. A. Simon, L. F Huber, Science 272, 841 (1996).
9. In situ pressure and temperature measurements made by the probe, when calibrated, should determine the probe descent rate profile. Meridional winds are expected to be less than 10 m/s based on remote observations and atmospheric models but higher winds cannot be definitively ruled out without direct observations.
10. A Doppler shift of the probe frequency of 10 Hz as received by the orbiter could be due to a vertical motion of about 2 m/s, a zonal motion of about 25 m/s, or a meridional motion of about 50 m/s. A shift of 10 Hz of the probe frequency as received at Earth could be due to a vertical motion of about 6 m/s, a zonal motion of about 2 m/s, or a meridional motion of about 25 m/s. These geometric factors changed during the probe descent as the relative geometry of the probe, orbiter, and Earth changed.
11. The probe telemetry rate was 128 bits/s on each channel. The telemetry was encoded as two symbols per bit to allow for error correction.
12. A. D. Seiff et al., Science 272, 844 (1996).
13. D. H. Atkinson, J. B. Pollack, A. Seiff, ibid., p. 842.
14. R. Woo, personal communication.
15. Because the probe antenna was not on the probe spin axis, spinning of the probe caused a similar, but smaller, effect.
16. By processing the VLA data in 0.1-s segments, the probe swinging is not resolved in the 10-Hz frequency bins. Processing the data in 1 -s segments is possible and does show the probe swing in the received frequency. Longer segments were not used in the wind profile reported here due to processing time constraints.
17. The pressure of 0.4 bar occurs 20 km above the reference 1 -bar level while 4 bar and 7 bar are 50 km and 75 km below the 1-bar level, respectively.
18. D. Atkinson, thesis, Washington State University (1989); J. B. Pollack, D. H. Atkinson, A. Seiff, J. Anderson, Space Sci. Rev. 60, 143 (1992).
19. D. Atkinson, thesis, Washington State University (1989); J. B. Pollack, D. H. Atkinson, A. Seiff, J. Anderson, Space Sci. Rev. 60, 143 (1992).
20. The design frequency of the probe USO-driven radio frequency was 1387.0 MHz. The frequency measured prior to launch was about 300 Hz higher than nominal with a drift that was not well determined. Our detected frequency was 465 ± 25 Hz higher than nominal.
21. F. H. Busse, Astrophys. J. 159, 620 (1970); Icarus 29, 255 (1976); P. J. Gierasch, ibid., p. 445; A. P. Ingersoll and D. Pollard ibid. 52, 62 (1982); K. Zhang and G. Schubert, Science 273, 941 (1996).
22. F. H. Busse, Astrophys. J. 159, 620 (1970); Icarus 29, 255 (1976); P. J. Gierasch, ibid., p. 445; A. P. Ingersoll and D. Pollard ibid. 52, 62 (1982); K. Zhang and G. Schubert, Science 273, 941 (1996).
23. F. H. Busse, Astrophys. J. 159, 620 (1970); Icarus 29, 255 (1976); P. J. Gierasch, ibid., p. 445; A. P. Ingersoll and D. Pollard ibid. 52, 62 (1982); K. Zhang and G. Schubert, Science 273, 941 (1996).
24. F. H. Busse, Astrophys. J. 159, 620 (1970); Icarus 29, 255 (1976); P. J. Gierasch, ibid., p. 445; A. P. Ingersoll and D. Pollard ibid. 52, 62 (1982); K. Zhang and G. Schubert, Science 273, 941 (1996).
25. F. H. Busse, Astrophys. J. 159, 620 (1970); Icarus 29, 255 (1976); P. J. Gierasch, ibid., p. 445; A. P. Ingersoll and D. Pollard ibid. 52, 62 (1982); K. Zhang and G. Schubert, Science 273, 941 (1996).
26. Since a constant adjustment to our wind profile has been made based on the first few seconds of probe-orbiter data, the profile should agree with the profile based on the probe-orbiter data for those first few seconds given identical modeling. Part of the difference in derived wind speed at the initial time in Fig. 1 is due to characteristics of the polynomial fit applied to the probe-orbiter profile; a revision of the probe-orbiter profile (reduction in speed of about 20 m/s) due to better understanding of the orbiter Doppler receiver accounts for the remainder of the difference. Using a revised vertical descent profile, based on calibrated in situ probe temperature and temperature measurements, the Jupiter zonal wind speed profile based on only the probe-orbiter Doppler measurements has changed from (7) to agree better in character with Fig. 1 and indicates a lower average wind speed by about 20 m/s. D. Atkinson, private communication (1996).
27. L. A. Sromovsky et al., Science 272, 851 (1996); B. Ragent et al., ibid., p. 854.
28. L. A. Sromovsky et al., Science 272, 851 (1996); B. Ragent et al., ibid., p. 854.
29. G. Orton et al., ibid., p. 839.
30. We thank the following for their assistance in performing this experiment; D. Atkinson for helpful comments and probe-orbiter measurements; J. Ulvestad, E. M. Standish, D. Spitzmesser, and D. Jones of JPL; R. Perley, K. Sowenski, J. Wrobel, P. Dooley, M. Claussen, B. Butler, and the VLA staff; K. Wellington, M. Kesteven, R. Ferris, and the staff of the Australia Telescope; T. McElrath, F. Nicholson, and the rest of the Galileo navigation team; M. Smith, C. Sobeck, R. Sakal, P. Garriga, D. Carlock, and the rest of the Probe Project. The Very Large Array, part of the National Radio Astronomy Observatory, is operated by the Associated Universities, Inc., under cooperative agreement with the National Science Foundation. The Australia Telescope is funded by the Commonwealth of Australia for operation as a National Facility managed by CSIRO. The research described in this paper was, in part, carried out by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.