V.V. Shevchenko, S.G.Pugacheva Sternberg State Astronomical Institute of the Lomonosov Moscow State University THE SECOND MOSCOW SOLAR SYSTEM SYMPOSIUM MOONS OF PLANETS MOSCOW 2011 IKI RAS LANDING SITE FOR A LUNA MISSION IN SOUTH POLE – AITKEN BASIN

The basin, which apparently belongs to the pre-Imbrian Period (~4 Ga), is the largest ring formation not only on the lunar surface but also in the entire Solar System. The nature and origin of the unique formation remain one of the most important problems in recent studies of the Moon. SOUTH POLE – AITKEN BASIN MYSTERY

The results of Clementine laser altimetry, the catalogs of absolute elevations of the far side of the Moon obtained based on the “Zond” survey materials, and the results of the ground-based studies of the lunar limb relief were initial data used to construct the hypsometric map (Shevchenko et al., 2007). A standard reference surface with a radius of 1738 km was used to count off heights.

KOROLEV TSIOLKOVSKIY CLAVIUS HIGHEST POINT ON THE MOON

Fe, %

Th,  g/g

Garrick-Bethell, Zuber (2009)

LRO/LOLA (2010)

WHAT IS THE SOUTH POLE-AITKEN IMPACTOR? A hypothetical impactor followed a trajectory (or orbit) oriented almost normally to the ecliptic plane (1). We assumed that a low impactor density can be one of the causes of an anomalously small “depth-diameter” ratio (2).

Proceeding from these two statements, we can make the hypothetical conclusion that the unique features of the SPA basin nature can be caused by the unusual basin formation as a result of the impact of a comet-type body.

The model following a South Pole-Aitken basin forming oblique impact event. For this simulation, the projectile direction was from south to north, the impact angle was 45°, the projectile diameter was 125 km, and the impact velocity was 15 km/s. Wieczorek et al., 2011.

LANDING SITE FOR LUNA MISSION IN SOUTH POLE – AITKEN BASIN MAXIMUM LIBRATION ZONE BASIN OUTER RING LANDING FAVOURABLE ZONE MAP OF THE LEND DATA

Conclusions: Lunar robotic missions to the South Pole - Aitken basin are proposed as the best means of addressing major problems concerning the early impact history of the inner Solar System, the nature of very large impact events, and the early differentiation of rocky planets.

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