Various spacecraft have attempted to address a hypothesized effect near the poles of the Moon called “peaks of eternal light”. BMDO/NASA’s Clementine spacecraft, ESA’s Smart-1 spacecraft, JAXA’s Kaguya spacecraft and NASA’s LRO spacecraft have all gathered data to try to see if there are any spots at the North or South Poles of the Moon that are illuminated year round. Such a location would be extraordinarily valuable real estate because you could simply deploy a solar array and generate all the power you need for a base or resource processing plant.
The French popularizer of astronomy Flammarion is often claimed to be the originator of the idea in 1879. He stated that there were possibly mountain peaks near the poles of the Moon which owing to their location were always in the sunlight. Fortuitously, in 2009, I came across a book in German by the astronomers Beer and Madler (1837) predating Flammarion’s idea by 42 years. In “Der Mond nach seinen kosmischen und individuellen Verhältissen oder allgemeine vergleichende Selenographie”, they say “..many of these peaks have (with the exception of eclipses caused by the Earth) eternal sunshine”. These guys were pretty smart I say!
This digitized book link occurred after I got a library to loan me an original edition, a nice an musty big crinkly paged book of which I copied the pages of interest.
Anyway, its not looking too good for these lunar peaks of eternal light using LRO data. Neither SMART-1 or Kaguya or LRO found any. Some lunar scientists suggest that maybe connecting various spots together either with power cables or beamed power would approach 100% illumination. Its too bad that the distance is fairly prohibitive (solar arrays can be very light, but harness and especially beamed power can get heavy). Others have suggested driving around to follow the Sun. Due to the way the shadows are cast by near and distant terrain, this also does not seem feasible (e.g. the light spot you are following suddenly disappears, but another appears behind you… which way to go??, its not like a cat following a laser light because the light effectively turns on and off… poor cat!). Other have suggested building high towers. Unfortunately, for this to work (100% illumination year round) the towers have to be very tall to help avoid high mountain caused shadows that sweep the poles. And even thought he gravity is less, >1 kilometer tall towers are pretty heavy (might as well just buy some batteries or fuel cells).
I discovered the Beer and Madler reference in January 2009.
The problem is this: is there any evidence of where the Apollo 11 flag fell? This was the first Apollo landing site and the astronauts did not place the flag pole sufficiently into the lunar surface so that upon take-off, one astronaut reported that it fell over.
Looking at the LRO images of the Apollo 11 site, the only one that seems to show something in the location of the flag.
This snippet of the site shows a bright spot near where the flag should be.
This was taken when the Sun was 8.77 degrees from directly above and the LRO imaging spacecraft was directly overhead. This means you would get the best reflection off a surface lying flat. No other LRO Apollo 11 site image shows anything I can see as a cast shadow or dot of the flag.
To better understand the layout of the site, here is a map from the Apollo 11 preliminary science report.
The below picture is from a link of an astronaut photograph taken from the LEM in the direction of the flag.
Discovery made on August 20, 2011 as documented in MoonZoo.
Examination of the LRO images for the Apollo 12 site also show that the flag is still on its pole and in condition sufficient to create a shadow.
This was discovered on August 23, 2011 and documented on the MoonZoo site.
Assembling the LRO images of the Apollo 16 site show that the flag is still on its pole and “solid”.
This discovery was made on August 22, 2011 as documented on the MoonZoo site.
Yes, based on Lunar Reconnaissance Orbiter (LRO) images, it is possible to deduce that the flag is still on its pole AND that it has not disintegrated over time. The flags were made of nylon so it logically seems like they should fall apart over 40 years of exposure to the vacuum and ultraviolet radiation of the lunar surface (not to mention micrometeorites). But when assembling the images from LRO of the Apollo 17 site based on images with different Sun angle but similar spacecraft-to-site angles, it became clear that the 3 foot by 5 foot flag shadow was visible as the site proceeded through the lunar day (15 Earth days of light, 15 of night). The pole is not visible since it is so thin (1 inch diameter) and the support rod that supported the flag from the pole was slightly less than 1 inch in diameter so it can’t be seen either. As anyone knows when watching their own shadow cast on Earth, at dawn or dusk the shadow cast is farther and longer the closer the Sun is to the horizon. In these LRO images, the same effect is happening and at lower Sun angles the flag’s shadow is spread over a longer distance making it more apparent. But also, because it is still mounted on the pole, the distance the shadow is from the point the pole was pounded into the lunar surface is further.
This is very amazing and inspirational that mere thin nylon…not at all “space rated”… can survive so long. We don’t know of course if the colors can still be seen on the nylon flag, but it may be a good assumption that the pattern could, at least, remain since UV would degrade the various colors differently.
This was discovered on August 20, 2011 in MoonZoo.
This blog site will share some interesting things found while working at NASA. Although these things are “reality” from my personal perspective, I must qualify that anything I say here must be considered my opinion and does not represent the official viewpoint, perspective or stance of NASA. Of course, many things are subject to interpretation and perhaps it would be hard to achieve consensus about just about anything.