Interior structure and seasonal mass redistribution of Mars from radio tracking of Mars Pathfinder

Science

Volumn 278, Issue 5344, 1997, Pages 1749-1752

  Folkner, W M ^a   Yoder, C F ^a   Yuan, D N ^a   Standish, E M ^a   Preston, R A ^a  

^a CALIFORNIA INSTITUTE OF TECHNOLOGY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

MARS; PATHFINDER MISSION; PLANETARY ROTATION;

ASTRONOMY; ATMOSPHERE; MATHEMATICAL MODEL; MEASUREMENT; PRIORITY JOURNAL; REVIEW; ROTATION; SEASONAL VARIATION;

FLIGHT EXPERIMENT; LONG DURATION; MARS PATHFINDER PROJECT; UNMANNED;

ATMOSPHERE; CARBON DIOXIDE; EXTRATERRESTRIAL ENVIRONMENT; FERROUS COMPOUNDS; ICE; IRON; MARS; PRESSURE; TEMPERATURE;

EID: 0030707833     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.278.5344.1749     Document Type: Review

References (28)

1. C. F. Yoder and E. M. Standish, J. Geophys. Res. 102, 4065 (1997).
2. For example, H. Y. McSween, Meteoritics 25, 757 (1994); J. C. Laul, Geochim. Cosmochim. Acta 50, 875 (1986).
3. For example, H. Y. McSween, Meteoritics 25, 757 (1994); J. C. Laul, Geochim. Cosmochim. Acta 50, 875 (1986).
4. W. M. Folkner et al., J. Geophys. Res. 102, 4057 (1997).
5. A. S. Konopliv and W. L. Sjogren, Publication 95-3, Jet Propulsion Laboratory, California Institute of Technology (1995); D. E. Smith et al., J. Geophys. Res. 98, 20871 (1995)
6. A. S. Konopliv and W. L. Sjogren, Publication 95-3, Jet Propulsion Laboratory, California Institute of Technology (1995); D. E. Smith et al., J. Geophys. Res. 98, 20871 (1995)
7. W. R. Ward, J. Geophys. Res. 79, 3375 (1974); J. Touma and J. Wisdom, Science 259, 1294 (1993).
8. W. R. Ward, J. Geophys. Res. 79, 3375 (1974); J. Touma and J. Wisdom, Science 259, 1294 (1993).
9. For example, L. M. Francois, J. C. G. Walker, W. R. Kuhn, J. Geophys. Res. 95, 14761 (1990).
10. A. Cazenave and G. Balmino, Geophys. Res. Lett. 8, 245 (1981); B. F. Chao and D. P. Rubincam, J. Geophys. Res. 95, 14755 (1990).
11. A. Cazenave and G. Balmino, Geophys. Res. Lett. 8, 245 (1981); B. F. Chao and D. P. Rubincam, J. Geophys. Res. 95, 14755 (1990).
12. The Pathfinder radio system operates at X band (8 GHz) compared with the S-band (2 GHz) radio system used by the Viking landers. The Doppler data noise caused by solar plasma is inversely proportional to the square of the radio frequency. The Pathfinder Doppler data have about 13 times less noise than the Viking lander Doppler data. The Doppler data noise is about 0.05 mm/s for data at 60-s intervals. The solar plasma also affects the round-trip range measurements. Calibrations for the solar plasma for some of the Viking lander data were determined from dual-frequency observations of the Viking orbiters. The Viking ranging data have a residual noise of ∼7 m for data with orbiter calibrations and ∼12 m for data with no orbiter calibrations. The Pathfinder ranging data taken so far have residuals of ∼3 m. The Pathfinder data analyzed here will be included in the mission data archive, to be available early in 1998 from the Planetary Data System.
13. 2) See (1) and F. W. Sears and R. W. Brehme, Introduction to the Theory of Relativity (Addison-Wesley, Reading, MA, 1968).
14. R. D. Reasenberg and R. W. King, J. Geophys. Res. 82, 369 (1977).
15. o = 65.323°. The node is measured with respect to the intersection of the martian mean orbit and the Earth mean orbit of J2000.
16. W. M. Folkner et al., Astron. Astrophys. 287, 279 (1994).
17. 2 = 0.001.9586 (4) the orbital eccentricity e = 0.09341, and the effective mean motion n = 191.408° per year.
18. For example, M. E. Davies et al., Celest. Mech. 63, 127 (1996).
19. o is the normal to the orbit. The explicit expression is dψ/dt = 1.0305 dα/dt + 1.6136 dδ/dt. The unmodeled nutations shift this estimate by about -100 mas/year. The rotation rate dW/dt differs from ω because the rotations about the pole α and δ are not eigen directions for the precession, which thus affects dW/dt.
20. R. D. Reasenberg, J. Geophys. Res. 82, 369 (1977); W. M. Kaula, Geophys. Res. Lett. 6, 194 (1979).
21. R. D. Reasenberg, J. Geophys. Res. 82, 369 (1977); W. M. Kaula, Geophys. Res. Lett. 6, 194 (1979).
22. B. Bills, Geophys. Res. Lett. 16, 385 (1989).
23. F. Sohl and T. Spohn, J. Geophys. Res. 102, 1613 (1997).
24. J. E. Tillman, N. C. Johnson, P. Guttorp, D. B. Percival, ibid. 98, 10963 (1993).
25. R. D. Rosen and D. A. Salstein, ibid. 88, 5451 (1983).
26. The model in (1) depends on cap size and ice mass distribution. The values quoted here assume uniform caps that extend to 65° latitude and sublimate and accrete uniformly over their surfaces.
27. The predicted triannual amplitude from air pressure and tides is 20sin(ℓ + 180°) mas and is reasonably close to the observed value 29sin(ℓ + 241°) mas.
28. We thank the Mars Pathfinder project team for their enthusiasm and assistance in acquiring and understanding the tracking measurements; R. Wimberly for recovery of the Viking lander Doppler data; and J. Williams and an anonymous referee for helpful suggestions. The research described in this paper was carried out by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA.