Astronaut Buzz Aldrin, Apollo 11 pilot, stands beside the US flag he and Neil Armstrong planted on the moon during the very visit by humans to the lunar surface (Photo: NASA)

Some of the most iconic moments in American history occurred when the Apollo astronauts planted U.S. flags on the lunar surface in the 1960s and 70s.

It’s been nearly 40 years since Apollo 17, the  final manned U.S. mission to the moon, left the last of six American flags on the its surface.

What happened to those flags, as well as other pieces of gear left by the Apollo astronauts, is apparently the source of endless fascination for a lot of people.

Image of the Apollo 17 landing site.  LRV in photo is the Lunar Roving Vehicle “Moon Buggy” (Image: NASA/GSFC/Arizona State University)

Questions on the topic are among the most commonly asked of the  Lunar Reconnaissance Orbiter Camera (LROC) mission, which recently took  photos of the lunar surface.

Those question have now been answered by high resolution images of the six Apollo landing sites taken by the mission’s Narrow Angle Cameras (NAC).

Images captured by the LROC cameras clearly show, not only the flags, but also the LEM descent stage, the lunar rovers and tracks left on the powdery lunar surface. The flags  are still standing, casting shadows on the moon.

“Personally, I was a bit surprised that the flags survived the harsh ultraviolet light and temperatures of the lunar surface, but they did,” blogged Mark Robinson, the principal investigator of the LROC mission. “What they look like is another question (badly faded?).”

Apollo 12 landing site. Notice the image also includes the Surveyor 3 unmanned spacecraft which landed on the moon April 20, 1967. (Image: NASA/GSFC/Arizona State University)

Only the flag planted by the first men on the moon, Apollo 11’s Neil Armstrong and Buzz Aldrin , is not erect.  Back when the two men took off from the lunar surface, Aldrin noticed  the flag was blown over by the exhaust from their  spacecraft’s  engine during liftoff.

To determine whether  the flags were still standing, the LROC team examined a timed series of images taken at different periods of the day, paying close attention to the shadows  circling the flags.

The  images  also captured other signs of the astronauts’ presence on the moon, such as the LEM descent stages of the lunar landers and various pieces of equipment  used for experiments or exploration.

Among them was the Lunar Roving Vehicle (LRV) or “moon buggy” as it was called, used during three Apollo  missions.

Also still there four decades later? Remnants of tracks marking where Armstrong and Aldrin took the first human steps on the moon.

Time lapse movie of a sequence of images highlighting the movement of the flag’s shadow at the Apollo 12 landing site. (Video: NASA/GSFC/Arizona State University)