flag
Detail from Apollo 12 photo AS12-47-6983 showing the deployed flag and its shadow. The latch failed on the pivot designed to hold the top edge of the flag out perpendicular to the pole on a supporting rod, so the flag hung limp. The flag was 5 x 3 feet (1.5 by 1.0 meters). Because the supporting rod is close to vertical, we can estimate that the part of the pole above ground is about 7 feet (2.1 m) tall and that the bottom of the flag is about 2 feet (0.6 meters) off the ground. On level ground, the far end of the shadow would be about 13 meters from the pole. The bottom of the flag is about 0.5 m above the surface and its shadow would be about 3 meters from the pole. Credit: NASA

The deploying of the Lunar Flag Assembly, as it was known officially, was repeated by each Apollo mission. Over the years, many have wondered what became of those historic banners. NASA officials never intended for the 5-by-3-foot nylon flags to last indefinitely. In fact, they didn’t really have a plan for the flag-raising until about three months before Apollo 11′s launch. As recounted in NASA Contractor Report 188251, the historic flag was purchased, literally, off the shelf for $5.50 at a local Sears store.

Aldrin reported seeing Apollo 11′s flag blown down by rocket exhaust as he and Armstrong blasted off the lunar surface, but it’s taken sharp-eyed detective work by Mark Robinson and his Lunar Reconnaissance Orbiter Camera team to learn the fate of all the flags. With a resolution of just 1.6 feet (0.5 meter) per pixel, LROC’s twin narrow-angle cameras were up to the task of recording the landing sites in remarkable detail. LROC images show that the banners are still standing at five of the landing sites — and even Apollo 11′s can be made out lying in the lunar dust.

“I get flag-picture questions all the time,” Robinson said, and the cameras record one or two Apollo sites every month as part of what he calls “cartography sanity checks.”

apollo17flag-anim
Strong shadows visible in a sequence of six LROC images. A patch of soil disturbed by the crew during flag deployment and picture taking shows up clearly in the fourth and fifth images. Credit: NASA / GSFC / Arizona State Univ.

Because they’ve been exposed to 40 years of harsh, unfiltered sunlight and space radiation, scientists think the Apollo’s flags are now pure white, their colorful stars and stripes bleached out completely. The fact that they’ve whitened over time actually makes them easier to spot. The moon’s extreme heat and ultraviolet conditions would probably destroy the nylon flags over time, he explained. “Personally, I would be surprised if there’s anything left on them,” Robinson said. “You know how if you leave a flag out over summer, how it starts to fade. Now, imagine the extreme UV environment on the moon, and the hot and cold cycling, and it’s been 40 years — so the flags are in pretty rough shape.”

LRO flies over these locations at various times of the lunar day, so its cameras sometimes record both the flags and their shadows. Moreover, the viewing angle isn’t necessarily straight down: on occasion the LROC team has angled the spacecraft’s view toward the illuminated sides of flags. So Robinson has assembled all of the LROC images for each Apollo landing site and created a series of digital “flip books” that show each scene with various lighting angles.


This “Day at the Apollo 12 Landing Site” video was just recently completed.

Posted by: Soderman/NLSI Staff
Source: http://www.hq.nasa.gov/alsj/ApolloFlags-Condition.html

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