What is the fate of the Apollo flag on the moon?

Extraordinary! The phrase was spontaneously spoken after LRO satellite images in unprecedented resolution unexpectedly uncovered one of the great puzzles in the landing saga of mankind on the Moon: the fate of the flag planted on the Moon's ground. Throughout the landing mission humans on the Moon that has lasted up to six times in the period 1969 to 1972 in the form of missions Apollo 11 to Apollo 17, except Apollo 13 which experienced an explosion of Oxygen tank on the command module so that the landing on the Moon had to be canceled, there are six flags has been plugged in at each landing point. All of them are US flags.

^{James Irwin salutes the United States flag on the Moon on August 1, 1971(apollo 15),credit image}

The flag became one of the hot topics in the discourse of human landing on the Moon. The skeptics presented the "fluttering" flag (which is, in fact, a statically stretched flag) as one of the reasons for rejecting a human landing on the Moon and thinking of it as bullshit and deceptions of the Cold War model. The optimists, on the other hand, regarded the flag as just a pole with no cloth. Because with nylon base material, it is difficult to imagine how the flag cloth can survive in a harsh Moon environment. Over the last four decades, the flag cloth was in a vacuum with exposure to extreme heat as high as 100 degrees Celsius in the Moon's day (throughout 14 Earth days) and then followed by cold freezing (as low as minus 180 degrees Celsius) on the night of the Moon (for 14 days Earth as well) with ultraviolet sun exposure, cosmic rays from the Sun and from all corners and micrometeorites. With such a harsh environment, it is not surprising that many who foresee flags on the Moon have been bleached, degraded, torn, or even so deeply dissected into dust.

^{Eugene Cernan on the lunar surface, December 13, 1972(apollo 17),credit image}

Is that right?

The launch of a Moon investigator called LRO (Lunar Reconnaissance Orbiter) on June 18, 2009, offers an opportunity to analyze how the fate of flags embedded on the Moon's surface is indirect. Satellites aimed at mapping the global topography of the Moon, characterizing spacecraft radiation in the orbit of the Moon and investigating the Moon's polar regions in search of the possibility of water existence on the Moon carrying very high resolution cameras capable of identifying objects up to 0.5 meters in size on the Moon thanks to their orbital heights which is only 50 km from the surface of the Moon) and its orbit (polar / polar orbit). This capability makes LRO satellites for the first time able to identify traces left behind in the past four decades on the lunar human landing program. The tracks include the rest of the Moon module, scientific inquiry devices, astronaut footprints and wheel plots of Moon explorers.

^{Flag assembly and shroud (NASA photograph S69-38748).,credit image}

The Moon Flag is not actually the target of the LRO investigation because, with the diameter of the flagpole only 2 cm, it is very difficult to identify it in the LRO image. The only possible way is to detect the shadows of the flag cloth under the sun. With a flag cloth measuring 1.5 meters x 1 meter for Apollo 11 to 15, the shadow of the flag cloth can be detected by LRO satellite cameras. By taking a number of imagery under various conditions of the Sun's lighting, for example since after rising, low in the eastern sky of the Moon, low in the western sky of the Moon until the sunset, how the dynamics of the shadow of the flag following it can be examined so that the location of the flag can be ascertained. Of course with a note if the flag is still there.

^{image of Apollo 16 landing site,credit image}

In addition to note also note Edwin Aldrin, Apollo 11 astronauts. In his book Return to Earth as thick as 239 pages, Aldrin said the flag that enforced with Neil Armstrong in Mare Transquilitatis, with a flagpole along the 2.7 meters with 0.6 meters of them plugged into a land of the Moon, has collapsed due to its position too close to the Moon module. So when the module is restarted (to return to Earth), a very strong burst of flue causes the flag cloth and its pole to collapse to the ground. The LRO satellite image does confirm Aldrin's record.

^{Left to right: Armstrong, Collins, Aldrin(Apollo 11),credit image}

So that only five points remain where the flag may still be left. Of the five points, LRO is glaringly able to identify flags (exactly shadow flags) at three points, namely at Apollo 12, Apollo 16 and Apollo 17 landing sites.

^{Apollo 12 Landing Site,credit image}

At the location of the Apollo 12 landing, the flag is plugged with a locking hinge mechanism on the overhead sufferer, causing the flag to become drooping, unlike the flag at the Apollo 11 landing point. However, the shadow of the flag cloth on the Moon's ground is clearly printed. Based on the image of Apollo 12 astronauts, when the Sun's height is 10 degrees above the eastern horizon, the shadows of the flag span as far as 2.8 meters to 12 meters from the base of the flagpole. With Moon soil at the landing sites tending to be flat, the shadow of the flag cloth at the Apollo 12 landing site is quite evident in the LRO image. By the time the Sun has just risen (the Sun's height is only 8 degrees above the eastern horizon), the shadows of the flag extend for 15 meters to the west. Likewise, as the sun approaches to set (the Sun's height 6 degrees above the western horizon), the shadow of the flag stretches to 20 meters, this time to the east.

^{Location of the Apollo 16 landing site,credit image}

While at the Apollo 16 landing site, the locking hinge mechanism works well so that the flag cloth can stretch out as it should. But as the effect is mounted too close to the Moon module, the burst of exhaust when the module is turned back causes the flagpole to tilt up to 30 degrees. Thus, the shadow of the flag cloth did not go as far as the shadow of the flag cloth at the Apollo 12 landing site. However, the LRO satellite is able to identify it well.

^{Apollo 17 landing site, photographed in 2011 by Lunar Reconnaissance Orbiter,credit image}

The same is true of the Apollo 17 landing site. The size of the flag is 20% larger than the other with the flagpole sticking deeper so that it can survive without sliding/tilting when exposed to the exhaust gas of the Moon module when restarted. This makes the LRO satellite able to identify the shadow of its flag well.

^{Apollo 14 landing site, photograph by LRO,credit image}

What about the fate of flags at the Apollo 14 and Apollo 15 landing sites? Photographs of Apollo 14 astronauts indicate that the flag is still mounted in place of an outstretched state when the Moon module is restarted. Even so at the Apollo 15 landing site. But LRO satellites cannot identify the shadows of flag cloths at both landing sites. What the cause is still unclear, although the alleged flag has been degraded from its pole or because of the less supportive conditions of the sun when the LRO takes its image.

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Reference :

1. https://en.wikipedia.org/wiki/Apollo_15
2. https://en.wikipedia.org/wiki/Apollo_17
3. https://www.hq.nasa.gov/alsj/ApolloFlags-Condition.html
4. http://www.skyandtelescope.com/astronomy-news/what-happened-to-the-flags-on-the-moon/
5. http://lroc.sese.asu.edu/about/specs
6. https://en.wikipedia.org/wiki/Buzz_Aldrin
7. https://en.wikipedia.org/wiki/List_of_Apollo_missions
8. https://en.wikipedia.org/wiki/Apollo_program
9. https://www.nasa.gov/mission_pages/apollo/missions/index.html