Reconnaissance of Mars satellites
Phobos and Deimos photographic reconnaissance feasibility during 1971 orbiter and 1973 Viking missions, studying trajectory
Campbell, J. W.↗
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Reconnaissance of Mars satellites
Phobos and Deimos photographic reconnaissance feasibility during 1971 Orbiter and 1973 Viking missions, studying trajectory
Campbell, J. W.↗
Phobos/Deimos missions
Phobos and Deimos missions, examining lander and lander/orbiter configurations and Titan- Centaur and space shuttle-Centaur launch systems
Harrison, E. F.↗
A study of system requirements for Phobos/Deimos missions. Volume 2: Phase 1 results, satellite rendezvous and landing missions
The feasibility of a satellite rendezvous, landing, and roving mission to the Martian satellites Phobos and Deimos is considered. Mission-oriented analysis, systems analysis, and conceptual design studies are presented.
Source record↗
On-board optical navigation data from Mariner '71.'
Satellite-star optical navigation, a new spacecraft navigation technique has been successfully demonstrated during Mariner 9's approach to Mars in mid-November. As Mariner 9 approached Mars, 21 TV pictures of its satellites, Phobos and Deimos, were taken and transmitted to earth. On earth, these pictures were carefully processed in order to locate the positions of the bright satellites against the relatively faint star background. The objectives and performance of the preflight and real time activities leading to the successful demonstration of satellite-star navigation data are described.
Duxbury, T. C.↗
A detailed analysis of Mariner nine TV navigation data.
Mariner 9 data analysis showed a good performance of the Mars probe planetary approach navigation systems and a good agreement between measured and predicted probe-approach characteristics. It was found that all operations were completed on time and that the calibration of the instruments and the observation of a greater-than-planned number of stars resulted in a higher-than-expected measurement accuracy. The key instruments of the Mariner were TV cameras taking pictures of Phobos and Deimos against a background of stars, calibrated sun and star sensors, and a scan platform. The error models used for optical navigation system elements, the calibration of the scan platform and of the TV cameras, and the image detection and location techniques are discussed in detail.
Breckenridge, W. G.↗
Evaluation of optical data for Mars approach navigation.
Investigation of several optical data types which can be obtained from science and engineering instruments normally aboard interplanetary spacecraft. TV cameras are assumed to view planets or satellites and stars for celestial references. Also, spacecraft attitude sensors are assumed to yield celestial references. The investigation of approach phases of typical Mars missions showed that the navigation accuracy was greatly enhanced with the addition of optical data to radio data. Viewing stars and the planet Mars was found most advantageous ten days before Mars encounter, and viewing Deimos or Phobos and stars was most advantageous within ten days of encounter.
Jerath, N.↗
Digital processing of Mariner 9 television data.
The digital image processing performed by the Image Processing Laboratory (IPL) at JPL in support of the Mariner 9 mission is summarized. The support is divided into the general categories of image decalibration (the removal of photometric and geometric distortions from returned imagery), computer cartographic projections in support of mapping activities, and adaptive experimenter support (flexible support to provide qualitative digital enhancements and quantitative data reduction of returned imagery). Among the tasks performed were the production of maximum discriminability versions of several hundred frames to support generation of a geodetic control net for Mars, and special enhancements supporting analysis of Phobos and Deimos images.
Green, W. B.↗
Mars physical parameters as determined from Mariner 9 observations of the natural satellites
Derivation of values for the Mars gravity field, as well as the mass and spin axis direction, by processing combined radio and optical data taken with the Mariner 9 spacecraft. The optical data consists of 62 TV photographs of Phobos and Deimos taken during the Mars orbiting phase of Mariner 9. The radio data consists of apoapsis state vectors obtained from 195 one-revolution fits of the Doppler data. A first-order analytic theory is used to model both the satellites and the spacecraft's motion. However, the shallow resonance condition of Mariner 9's orbit necessitated development of a partial second-order theory to model the long-period perturbations which derive from Mars even-order tesseral harmonics. Use of an analytic theory allows rapid and inexpensive processing of both data types simultaneously. The results are in good agreement with those previously published from Mariner 9 Doppler and landmark data.
Born, G. H.↗
The new Mars: The discoveries of Mariner 9
The Mariner 9 encounter with Mars is extensively documented with photographs taken by the satellite's onboard cameras, and an attempt is made to explain the observed Martian topography in terms of what is known about the geomorphological evolution of the earth. Early conceptions about the Mars surface are compared with more recent data made available by the Mariner 9 cameras. Other features of the planet Mars which are specifically discussed include the volcanic regions, the surface channels, the polar caps and layered terrain, the Martian atmosphere, and the planet's two moons--Phobos and Deimos.
Hartmann, W. K.↗
Mariner Mars 1971 television picture catalog. Volume 1: Experiment design and picture data
A compilation of Mariner 9 television data is presented for the study of the planet Mars and of its two satellites, Phobos and Deimos. The concept of the basic mission, camera characteristics, and various processing techniques of the raw television data recovered from the spacecraft are discussed. Data are arranged into the following disciplines; (1) mapping and geology, (2) polar studies, (3) geodesy, (4) variable surface features, (5) atmospheric phenomena, and (6) satellites. Reproduction and arrangements of approximately 3000 individual pictures and photomosaics are provided.
Cutts, J. A.↗
A Mariner 9 Atlas of the moons of Mars
During its active lifetime Mariner 9 obtained 32 high-resolution pictures of Phobos, and 9 of Deimos. The spacecraft orbit was adequate for about 80% complete coverage of Phobos. However, the coverage of the outer satellite was restricted to the Mars-facing side. The approaches used in processing the pictures are discussed. For each satellite picture a coordinate grid of the satellite was obtained with the aid of a computer.
Veverka, J.↗
Photometric properties of the Martian satellites
New photoelectric observations yield V(1, alpha) equals 12.95 + 0.036 alpha + or - 0.05, B-V equals 0.65 + or - 0.03, and U-B equals 0.18 + or - 0.03 for Deimos and V(1, 0) equals 11.9 + or - 0.2 for Phobos. The derived geometric albedos of both satellites are near 0.065. Combined photometric and polarimetric results lead to the conclusion that the satellites have dusty surfaces and are possibly basaltic but more likely carbonaceous in composition.
Zellner, B. H.↗
Mars - Satellite origin and angular momentum
The origin of Phobos and Deimos is considered with a view to accounting for the existence of very small satellites with circular orbits in the Martian equatorial plane, and simultaneously for the suspected angular momentum deficiency of the Mars system. All models considered failed to satisfy at least one requirement, and the problem is considered more puzzling than is at first apparent. The Martian angular momentum deficiency, if physically significant, may be unrelated to the present satellites' origin, but might relate to a large ancient satellite, long ago destroyed. Accretion onto Mars of large amounts of asteroidal dust brought in by Poynting-Robertson drag may have some bearing on the angular momentum problem.
Hartmann, W. K.↗
The new Martian nomenclature of the International Astronomical Union
A new nomenclature for Martian regions and topographic features uncovered by Mariner 9, as officially adopted by the International Astronomical Union, is described. About 180 craters generally of diameters greater than 100 km have been named, as well as 13 classes of topographic features designated catena, chasma, dorsum, fossa, labyrinthus, mensa, mons, patera, planitia, planum, tholus, vallis, and vastitas. In addition seven craters and the Kepler Dorsum are named on Phobos, and two craters on Deimos. Coordinates and maps of each named feature are displayed.
De Vaucouleurs, G.↗
Secular acceleration of Phobos and Q of Mars
Reductions of Mariner 9 TV data of Phobos and Deimos tend to corroborate the existence of a secular acceleration of Phobos commensurate with two recently reported values based on a reprocessing of earth-based data. These values of secular acceleration have been used together with Mariner 9 data on the physical size of Phobos and earth-based photoelectric observations which infer a carbonaceous composition for Phobos to place upper and lower bounds of 50 and 150, respectively, on the tidal dissipation function of Mars. The corresponding upper and lower bounds on the tidal lag angle are 0.19 and 0.57 deg.
Smith, J. C.↗
The equilibrium figures of Phobos and other small bodies
Computations of figures of hydrostatic equilibrium for isolated rotating bodies are discussed. It is shown that the theoretical figure of equilibrium for Phobos is a triaxial ellipsoid whose a and b axes differ by about 25% and that this difference is less than 2% for Deimos. A density of less than 3.9 g/cu cm is estimated for Phobos. Equilibrium figures are also examined for the inner satellites of Jupiter and Saturn as well as for small asteroids.
Soter, S.↗
Rotation histories of the natural satellites
Recent advances in the theory of rotation are combined with traditional approaches to study the rotational evolution of the 33 known natural satellites. A calculation similar to that reported by Burns and Safronov (1973) is applied to each satellite to obtain the characteristic time of decay of any wobble motion to smooth rotation about the principal axis of maximum moment of inertia. Stability criteria and capture probabilities are calculated for the 3/2 spin resonance. Results show that only the regular satellites and Iapetus, Hyperion, Triton, and the moon are tidally evolved. Of these, 13 have confirmed synchronous rotation periods; capture probabilities into the 3/2 resonance indicate that none of the remaining 10 should be captured in nonsynchronous, commensurate spin states. For the most part, the irregular satellites retain their original spins except for a relaxation to principal axis rotation. Tidal evolution of the obliquities of the satellites is evaluated in the framework of the generalization of Cassini's laws for the moon. Nearly resonant, forced librations in longitude of 4.8 and 0.5 deg are calculated on the basis of the observed shapes of Phobos and Deimos, respectively.
Peale, S. J.↗