45 Years Ago Today…

45 years ago today, man successfully returned rocks from another world for study on Earth. On Thursday, July 24, 1969, astronauts Armstrong, Aldrin, and Collins splashed down somewhere in the Pacific. They had brought with them a little over 20 kg of rock that they’d collected from the first jaunt on the moon’s surface. By the end of the Apollo program, over 300 kg of lunar rock and soil had been brought back for study by terrestrial scientists.

Lunar mare basalt collected by Apollo 11 astronauts.
Lunar mare basalt collected by Apollo 11 astronauts.

After a few weeks of quarantine, the Apollo 11 lunar samples were released to various labs for scientific scrutiny. One such lab was headed by Preston Cloud at UC-Santa Barbara, who was funded by NASA’s Exobiology program. Cloud was a geologist who had played a key role in discovering that microorganism fossils were intimately related to the banded iron formations found around Lake Superior. These 2.7 billion year old deposits heralded the introduction of the Earth’s oxygen atmosphere. Cloud was an expert in identifying the chemical and microscopic evidence of ancient fossil life, which was his job with the lunar samples. His lab concluded that these rocks do not, and never did, contain evidence of living material.

As more samples came from the successive successful Apollo missions, the amount of research done on them skyrocketed. They became the most studied geologic samples on Earth. We discovered that the Moon is a differentiated object – the highland suite of rocks represent rock that formed from more magmas more evolved than that found in the mare basalts. We discovered that the Moon is genetically similar to the Earth – oxygen isotopes within the lunar samples matched the ratios found in Earth rocks. We discovered that the Moon’s surface is old, as old as the Earth’s oldest rocks. And we discovered that the rocks formed with very little, if any, interaction with water.

After the Apollo program was shut down (yes, there was supposed to be an Apollo 18, 19, 20, and a followup Mars program), interest in the lunar rocks waned, and they lay virtually fallow for a decade. The 1980s were a decade of scientific pessimism. All of the space program’s eggs were thrown into the Space Shuttle’s basket. Nixon had shut down not only the Apollo program for his Space Transport System (the Space Shuttle), but also the NERVA nuclear rocket program. This smallification of space operations was the death knell for hopes of a trip to Mars in the 1980s. The public’s eyes, and those of Washington, remained locked on the Earth through the dirty decade of the 1980s.

But, something happened in the early 1990s. Excitement began to grow once again for space exploration. New missions to the Moon and Mars were planned. In preparation for the Lunar missions, a renewed interest in looking at the Apollo lunar samples took hold. The Clementine mission to the Moon, which produced the first (!) global map of the Moon, also gave tantalizing hints of the existence of water within the permanently shadowed regions within polar craters. Since then, study of that 300 or so kg of lunar rock has exploded. In 2011, conclusive evidence was finally found of water within Apollo 17 samples.

This graphic shows how many articles were published with “apollo lunar samples” in the abstract, by year. Note the dry period of the 1980s, and the explosive wet period in the past two decades. We need to go back to the Moon.

Robotic sample return from Mars is the number one goal of NASA’s most recent Decadal Survey. But sample return by humans is the most efficient and by far the most effective. The only other samples brought back from the moon (besides the 48 kg of lunar meteorites found on Earth so far) was from the Russian Luna missions. They brought back about a third of a kilogram. We need much more! For example, all the rock and soil brought back from the moon are igneous in origin. Are there metamorphic or sedimentary rocks that we could find?

Let us continue on the path first brooked by the Apollo 11 mission. Let us go back to the Moon, and on to Mars. Let us bring back samples, so we can continue to learn what universe it is in which we live.

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