The Face of the Moon

41. Ranger IX Lunar Chart: Alphonsus.

-- St. Louis: United States Air Force, 1966. (Lunar Charts and Mosaics, RLC (series)-14)

The U.S. Air Force issued a series of charts in 1966 based on the Ranger missions. There were seventeen maps published in the RLC series; the first five show increasingly detailed maps of the Fra Mauro/Riphaeus region; maps 6-12 do the same with the Sabine/Ritter region, and maps 13-17 chart the crater Alphonsus.

Alphonsus was at one time slated for the Apollo 17 mission. It was of interest to selenologists because it was "pre-Imbrium," that is, formed of material that predated the impact that created the Imbrium Basin and showered much of the moon with debris. It was also thought at the time that many of the small craters on the Alphonsine floor were volcanic in origin, and sampling might give clues as to when tectonic activity ceased in the moon's interior. Apollo 16 raised doubts about lunar volcanism, however, and Alphonsus was finally replaced by Taurus/Littrow as the site for Apollo 17.

image - click to enlarge

RLC 14 is the second of the Alphonsus sequence; it is filled by the crater, and corresponds more or less to the exhibited photograph from Ranger IX (see item 40). The impact point is indicated on the upper right floor of the crater; the small box indicates the area covered by the next chart, RLC 15. Other lines indicate the trajectory of Ranger IX and the tracks of the six camera axes.

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