Exposing PseudoAstronomy

July 15, 2009

The Apollo Moon Hoax: Why Is There No Lunar Dust on the Lander’s Footpads?

The Apollo Moon Hoax: Why Is There No Lunar Dust on the Lander’s Footpads?


For my continuing series in the Apollo Moon Hoax, I am going to address a claim that follows along the lines of the NASA stagehands not doing their job right — not placing any dust on the lunar module’s footpads.

All posts in this series:

The Claim

The basic claim goes as follows: When looking at the pretty pictures of the golden footpad of the Apollo lunar module (LM — see photo below), there doesn’t appear to be a single grain of dust on it, as though the module was just “placed there.”

Lunar Module Footpad - AS11-40-5926

Lunar Module Footpad - AS11-40-5926

Obviously, the NASA people who didn’t put the dust there were trying to tell future generations that this was a faked event, leaking this information out so no NASA higher-ups would realize.

The Lunar Atmosphere vs. Earth’s Atmosphere

There isn’t any. Simply put, the mass of the entire atmosphere of the moon is less than the amount of gas expelled by each Apollo descent engine.

As a result, if you were to pick up a handful of lunar dust and drop it, it would fall straight down with an acceleration about 1/6th that in Earth’s gravity. It would land directly below where you released it.

But it would appear to fall faster than that when compared with actually dropping flour-like substances on Earth. This is due to Earth’s atmosphere, which adds a resistive force to the dust settling down. In addition to this resistive force preventing its downward motion, Earth’s atmosphere is not still – it moves around. This allows any light material to billow out, creating clouds of material, and rarely landing directly below the location you released it.

The Lunar Module’s Descent Engine Shut-Off

The Apollo LMs had an antenna that when it came into contact with the lunar surface would trigger a light inside the craft. This light would be a signal to the astronauts to shut off the engine. Hence, the engine would be shut off before the craft landed.

Putting the Pieces Together to Debunk the Claim

At this point, we have two facts. First, lunar dust will drop straight down if it is released – be it from an astronaut that picks it up or from the force of a rocket engine’s exhaust (which, while not strong enough to create a crater was strong enough to suspend lunar dust). Second, the Apollo engines were shut off before the craft landed.

Consequently, as soon as the engines shut off, the source of a temporary atmosphere that surrounded the craft was terminated, and the dust that was suspended in it immediately dropped towards the lunar surface. The craft still had both a horizontal component to its trajectory, and the legs were above the majority of any of the temporary atmosphere that suspended the dust.

Hence, when the craft landed, it landed both to the side of the settled dust, and the dust would have already settled before the craft touched down, preventing any from being deposited on the LM’s footpads.

Final Thoughts

This claim is yet another one that hinges upon a perceived anomaly. And yet, this anomaly is common sense here on Earth but our common sense does not serve us well when trying to understand the lunar environment. When you hear a hoax claim, try to think about what would really happen in the environment of the moon, and you will be on your way to debunking the claim yourself.

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