Mariner 9: An instrument of dynamical science

Jordan, J. F.; Lorell, J.

doi:10.1016/0019-1035(75)90194-3

Cited by 29 publications

(14 citation statements)

References 32 publications

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“…Mariner 9 observations and a model of the gravity field (8) were used to define an atmospheric pressure surface of 6.1 mbars as the origin of topography (zero elevation) for Mars. Subsequently, various measurements were combined into digital terrain models (DTMs) (9) that were of variable spatial resolution and typically characterized by vertical errors of ϳ1 to 3 km (10).…”

mentioning

confidence: 99%

Topography of the Northern Hemisphere of Mars from the Mars Orbiter Laser Altimeter

Smith

Zuber

Frey

et al. 1998

Science

198

120

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The first 18 tracks of laser altimeter data across the northern hemisphere of Mars from the Mars Global Surveyor spacecraft show that the planet at latitudes north of 50°is exceptionally flat; slopes and surface roughness increase toward the equator. The polar layered terrain appears to be a thick ice-rich formation with a non-equilibrium planform indicative of ablation near the periphery. Slope relations suggest that the northern Tharsis province was uplifted in the past. A profile across Ares Vallis channel suggests that the discharge through the channel was much greater than previously estimated. The martian atmosphere shows significant 1-micrometer atmospheric opacities, particularly in lowlying areas such as Valles Marineris.

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mentioning

confidence: 99%

Topography of the Northern Hemisphere of Mars from the Mars Orbiter Laser Altimeter

Smith

Zuber

Frey

et al. 1998

Science

198

120

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“…For arcs of four orbits or less, the effects are said to be negligible. 5 However, a quantitative analysis 2 by the same authors indicates that these accelerations can bias fourth-degree terms by 100% of their values. The expected level 2 of these unmodeled accelrations is about 10 ~n km/sec 2 .…”

Section: Spacecraft Forcesmentioning

confidence: 96%

Spherical Harmonic Representation of the Martian Gravity Using a Short-Arc Technique

Daniels

Tolson

Gapcynski

1977

Journal of Spacecraft and Rockets

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Planetary gravity fields are determined primarily from Doppler tracking of orbiting spacecraft, which are typically in high-eccentricity orbits. Thus, the noncentral gravitational components perturb the orbit primarily in the vicinity of periapsis. To find a computationally efficient technique and to reduce the influence of unmodeled forces on the spacecraft, an analysis has been performed of the effectiveness of processing only data in the vicinity of periapsis using multiple short arcs. Although similar short-arc techniques have been utilized for Mascon studies, this analysis is based on a spherical harmonic representation of the gravity field of Mars. Mariner 9 data are processed for the study, using 1-, 2-, 3-, and 4-hr arcs and estimating gravity fields from fourth through seventh degree. The resulting gravity fields are intercompared and also compared with previously published results.

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“…This has proved that the Martian topography does correlate with the gravitation potential. But, on the other hand, it was discovered that the higher degree spherical harmonics are not stable and only the lower degree harmonics have demonstrated stability, especially those coefficients of the fourth degree (Jordan and Lorell, 1975). Also, as Jafar pointed out (Jafar, 1975), the coefficients in the spherical harmonics between the second and third degree show a strong correlation with the topography and starting with the fourth degree, the correlation becomes weak.…”

Section: The Gravity Field Of Marsmentioning

confidence: 99%

“…The spherical harmonic expansion used to represent the Martian gravity field potential is: If we set -J = C and since the Martian mass constant, n no km^ 9 y = GM = 42828.439 /sec , has been previously determined (Christensen, 1975), then the equation can be changed to be expressed in terms of radial deviations from a mean sphere as (Jordan and Lorell, 1975): has been programmed as a subroutine for the adjustment of all the data from the various sources used in this experiment as will be discussed in later chapters. It is also programmed on the XY plotter at N = 4, the fourth degree.…”

Section: The Gravity Field Of Marsmentioning

confidence: 99%

Mars synthetic topographic mapping

1978

Icarus

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Mariner 9: An instrument of dynamical science

Cited by 29 publications

References 32 publications

Topography of the Northern Hemisphere of Mars from the Mars Orbiter Laser Altimeter

Topography of the Northern Hemisphere of Mars from the Mars Orbiter Laser Altimeter

Spherical Harmonic Representation of the Martian Gravity Using a Short-Arc Technique

Mars synthetic topographic mapping

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