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Date Entered: 1 November 1989
Date Last Revised: March 1993
The landing site includes a wide impact basin (150 km diam.) in the Elysium Planitia, and a large valley between Al' Qahira and Ma'adim Valles. The landing site is southwest of Apollinaris Patera, at 15.5 deg. S, 190 deg. W. The average slope does not exceed 1.5%. The terrain is open and allows a good margin for landing operations. Few obstacles are visible according to available data. The site shows few major impact craters or linear hazards.
Scientific Rationale
Non-ambiguous geological diversity including volcanic material, possible tectonic activity, impact crater material, plain material, eolian deposits, plateau material, and channel material.
Objectives
a) Definition of martian volcanism system by lava sampling.
b) Definition of atmospheric model by eolian deposit samples.
c) Contribution to martian water hypothesis by channel investigations.
d) Contribution to the geological layers by rock sampling.
e) Opportunity for biological experiments in a past water-rich terrain.
Landing site and point a: Collection of lava samples in the Elysium volcanic region. Erection of seismic stations. Collection of eolian deposits. Erection of meteorological stations to analyse possible cathabatic winds at the plateau/plain margin.
Traverse 1 and point b: At valley-plain margin, collection of eolian deposits, channel material, lava, plateau material (down the valley slopes) on a small area. Proceed with corings at shallow depth to characterize different levels of deposits. Possible evidence of water transport. Core may reveal a succession of eolian and channel deposits. Possible wind deflated lava coming from the upper plateau and some gravity accumulations of plateau materials down the slopes.
Traverse 2 and point c: Collection of sediment samples upstream of point b. Comparison with point b samples may indicate the transport capacity of a supposed martian runoff. Images of slopes to document possible existence of terraces in order to understand the flow variations.
Traverse 3 and point d: Collection of slope accumulation samples along traverse. Collection of crater ejecta material at point d.
Traverse 4 and return to lander: Preparation of samples for Earth return mission.
Potential Problems
To be determined.
Trafficability
The average slope does not exceed 1.5%. The terrain is open and allows a good margin for landing operations. Few obstacles are visible according to available data. The selected landing site shows few major impact basins or linear hazards.
Estimated Traverse Distance
Total traverse distance 105 km.
TRAVERSE:
1. Rover traverse from site a to b 30 km
2. Rover traverse from site b to c 15 km
3. Rover traverse from site c to d 45 km
4. Rover traverse from site d to a 18 km
5 month mission time.
Exobiology Significance
The exbiology site is located at 15.5 deg. S, 188.5 deg. W in an ~200 km diameter crater-basin. Multiple-level stream terraces are inferred to be present within the confines of the major channel, suggesting that there were multiple episodes of downcutting. The downcutting of the channels is problematic, but may have been regulated by changes in base level as a result of drops in lake level within the crater basin, or by local tectonic uplift. The size of the channel system and inferred presence of terracing, suggests that the period of fluvial activity was sustained for some time.
The exobiology landing site is a likely place for fluvial-deltaic sediments, and potentially, for marginal lacustrine deposits. Fluvial-lacustrine deposits are of interest to Exobiology because they may contain a fossil record, and the apparent absence of younger volcanics covering the basin floor, suggests that such deposits may lie at or near the surface in the vicinity of the proposed landing site. Coarser-grained units may contain clasts derived from fossiliferous formations exposed in the older Noachian source area to the south. Under appropriate geohydrological conditions, marginal lacustrine facies are often a locus for primary carbonate mineralization, which favors the preservation of fossils and organic matter.
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