A plane silhouetted against the moon

Say you are NASA and you want to set up a lunar outpost, and you want lots of sunlight to power it. Well then, Houston, you?ve got a problem. Since the same side of the moon always faces the earth, and it goes from fully illuminated to dark each month, finding a place with permanent sunlight would seem to be difficult at best.

But scientists think they may have found such a place. Poring over images from a 10-year-old lunar mission, they have located an area near the moon?s north pole that is fully illuminated, at least in summer.

Dr Ben J. Bussey of the Johns Hopkins Applied Physics Laboratory and colleagues compiled an illumination map of the polar region using images from the Clementine spacecraft, which orbited the moon in 1994. Several fully sunlit spots were found along the north rim of Peary crater, an impact crater near the pole that is about 45 miles in diameter. The findings were published in the journal Nature.

Scientists have long thought there may be areas of permanent sunlight near the poles because, unlike the earth, the moon is tilted only slightly ? about 1.5 degrees ? from its rotational axis. So an area near the poles that is at high enough elevation may even catch sunlight during the winter, when it is tilted away from the sun. The rim of the Peary crater is such a highland area, Bussey said, roughly a mile higher than the crater floor.

Because the images were obtained only during what is the lunar summer, it?s not known whether they are illuminated in winter as well. ?But they are probably the most illuminated areas on the Moon,? Bussey said.

That bodes well as a location for a base. ?You?d have a permanent source of solar energy, and in an outpost, energy is at a premium,? Bussey said. ?If you can do it with solar rather than taking a nuke with you, that?s good.? The area would also have a relatively constant temperature, about minus 60 degrees Fahrenheit. By contrast, areas near the equator fluctuate from about 200 degrees above zero to 240 below. A constant temperature would be much less of a problem for dwellings and equipment.