One of the all-time questions that people ask about any big telescope is “can you see the flags on the Moon?” The answer for all ground based, and Earth orbiting (e.g the. Hubble Space Telescope) is no for a variety of reasons: too small at that distance, on too bright of a surface, etc. In fact the Hubble website has this question (with answer) in their FAQ! With the fantastic images from the Lunar Reconnaissance Orbiter Camera (LROC) in Lunar orbit however, we can indeed see many of the objects left behind by the Apollo astronauts. The landers, footpaths, rovers, and science experiments are all visible in amazing detail. For example, below is a recent LROC image of the Apollo 11 landing site at the Sea of Tranquility.
LROC image credit NASA / GSFC / ASU
But what about the flags? Now in many of the images there seems to be something around where the flags were planted, but it’s really tough to tell anything about them from a single image. Even with shadows, it is hard to make out if the shadow is from the flag, or from the flagpole! Quite a number of people, myself included, have postulated that the flags on the Moon have deteriorated away during the 4+ decades that these flags have been there. Harsh UV, charged particle, and micrometeorite bombardment – all things that our atmosphere and magnetic field protect us from – might have easily destroyed a standard nylon flag, which indeed was all that the Apollo flags were.That said, you can indeed make out the “flag” site of most of the Apollo landings in the LROC images, and something is there! But are they the flags, or just the poles with a pile of nylon dust? A recent round of LROC observations has answered that question: Despite my pessimism on their survivability, the flags are still there. Having now observed the landing sites at many angles, the LROC team has been able to look at the shadows cast by the flags, and those shadows not only match those expected by a flag+pole, but change orientation with the sun from image to image! Below is a recent image of the Apollo 17 site, along with a blow-up of the portion with the descent stage and flag – that shadow is certainly more than just the pole!
LROC image credit NASA / GSFC / ASU
The LROC team has also made an animation out of the still images of the Apollo 12 site, you can watch the shadows move around during a “lunar day” reconstructed from the LROC observations:
Ok, to be fair, the flags might not be intact. While we can now see that they are still standing, the 40+ years they’ve spent on the Moon may have “bleached” out their colors, but it’s still pretty flipping cool that 5 out of 6 Apollo Flags have been found. Buzz Aldrin mentioned that he thought he saw the flag get knocked over as he and Neil Armstrong took off from the Moon, and what do you know, he was right. The only Apollo flag not identified in the LROC images is Apollo 11’s.
