Constant illumination at the lunar north pole

摘要

Images returned by The spacecraft Clementine have been used to produce a quantitative illumination map of the north pole of the Moon, revealing the percentage of time that points on the surface are illuminated during the lunar day. We have used this map to identify areas that are constantly illuminated during a lunar day in summer and which may therefore be in permanent sunlight. All are located on the northern rim of Peary crater, close to the north pole. Permanently sunlit areas represent prime locations for lunar outpost sites as they have abundant solar energy, are relatively benign Thermally (when compared with equatorial regions), and are dose to permanently shadowed regions that may contain water ice. Because the Moon's spin axis is nearly perpendicular (about 1.5 deg) to the ecliptic plane, astronomers have long con sidered that areas of illumination extremes may exist near the lunar poles. Topographic lows, such as the floors of impact craters, can be permanently in shadow, whereas high areas could in theory be in constant sunlight. Permanently shadowed regions are extremely cold and may contain deposits of water ice. Conversely, the temperature in a permanently lit zone is relatively mild and constant because of the grazing insolation. The temperature at the lunar equator fluctuates from - 180 deg C to 100 deg C, but the surface temperature for a constantly sunlit polar region has been stimated from modelling to be roughly - 50 ± 10 deg C.Aregionwith this relatively benign temperaturerange represents an attractive site for building hardware designed for long-term use.