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Learning Apollo – Sky & Telescope



Apollo 11 opened a new field for exploration, but on the way, NASA squeezed out as much science as possible from this and subsequent missions landing on the moon.

From the mandate of President John F. Kennedy & # 39; from 1961 Until Apollo 17 left the moon in 1972, Apollo dealt with geopolitics. Nevertheless, NASA squeezed as much learning from the program as possible, both in space and on the moon, and the quantity and quality of science only increased as the mission progressed.

When Apollo 11 delivered Neil Armstrong and Buzz Aldrin to the surface of the Moon, the mission was the culmination of the engineering phase of Apollo. Still, during their moonwalk, Armstrong and Aldrin collected geological samples – very scientifically useful samples that informed scientists about the history and composition of the moon and helped NASA that the surface of the moon was lacking organisms that could endanger land life. Armstrong and Aldrin also created a simplified version of the instrument package – the Apollo Lunar Science (ALSEP) experiment package – which would be implemented in subsequent missions.

Buzz Aldrin and the first ALSEP

Buzz Aldrin wears a laser reflector in her right hand and a seismometer in the left.
NASA

The Apollo 11 crew made good progress, but when JFK's mandate was met, science played a greater role starting with Apollo 12, when the commander of the mission Pete Conrad and the lunar module pilot Alan Bean spent two days on the moon's surface, performing the moonwalk every day and collecting more materials than their predecessors.

Alan Bean and the ALSEP package

Alan Bean is working on the installation of a part of the ALSEP package. (Read detailed technical information about the image here.)
NASA

Later, beginning with Apollo 15, each landing crew carried out three-day walks on the moon, riding on a lunar pram to overcome greater distances during exploration, which was particularly difficult in field geology. To achieve this, the crews received hundreds of hours of training, giving them the equivalent of master's degrees in geology – with the exception of Harrison "Jack" Schmitt from Apollo 17, who already had a PhD. in geology. In the middle of it all, NASA began to break the Saturn S-IVB stages and lunar modules rising to the moon, generating moon shakes, which impact on seismometers – contained in the ALSEP stations – would reveal information about the interior of the moon.

The importance of interactions

The founder of NASA's astrogeology program was Eugene Shoemaker, who grew in importance when he showed that the Barringer rater in Arizona was the result of a strike event, not a volcanism. This discovery reinforced the idea that moon craters, pools and other lunar elements were also sculpted by impact events.

Hemisphere of the Moon

The nearest page (left) and on the other side of the Moon, as recorded by the Lunar Reconnaissance Orbiter camera. Oval indicates the location of the South Aitken basin, one of the largest shock basins in the solar system.
NASA / Arizona State Univ.

Examining samples from the regions of mares (lowland) and terra (mountain), scientists confirmed that impacts were the dominant force shaping the surface of the Moon, as well as the surface of all internal planets billions of years ago. By dating the samples, the scientists were also able to calibrate the age estimates determined by counting craters, which allowed them to date places from which they could not collect samples – including craters from other planets.

Apollo's science covered a range of topics: lunar dust analysis, lunar potential, photography and moon mapping, secular acceleration of the Moon, which gradually takes them out of the Earth, continental drift on Earth, cosmic medicine and radiation biology. But the importance of influence was the main discovery that concerned many long-lasting questions about the moon. One such question was, for example, why Maria seems darker than terrae?

Apollo 15 Moon rock

This rock sample from Apollo 15 is basically basalt.
NASA / Johnson Space Center

Analysis of Apollo samples confirmed that Maria was covered with basalt, indicating that lava spread after newer impacts, which cracked the shell deep enough to release the magma from the mantle.

The origin of the moon

Apollo's research also concerned the origins of the Moon. When Armstrong, Aldrin and Michael Collins arrived on the Moon in 1969, Three major hypotheses have existed for almost a century. One was the co-accretion hypothesiswho assumed that the Moon and Earth formed together in space and that they were chemically identical. However, the moon samples that Apollo astronauts brought to Earth showed that the Moon is relatively poor in iron. An early analysis also showed that there were no volatile compounds in the Apollo samples, such as water.

Alternatively, some scientists have suggested that Earth caught the Moon, which originally formed as a separate body near our planet. In fact, Apollo's analysis of the samples shows that the ratios of oxygen isotopes on two bodies fit, probably solid evidence that the two worlds were formed at approximately the same distance from the Sun. However, the lack of iron in the moon and the lack of volatile substances prove that it could not be created alone near the Earth.

The birth of the moon?

In the 1970s, scientists proposed that an object the size of Mars could collide with Earth and throw enough matter into orbit to create the Moon.
Don Davis / The New Solar System

Ultimately, these shortcomings led to a gigantic impact hypothesis, first proposed in 1975. The idea is that a planet the size of Mars, since naming Theia, affected the early Earth after both worlds have already grown from the solar planetary disk. They had enough time to split into a shell, coat and core. When Theia hit the Earth, the cores of both worlds gave our planet iron. Meanwhile, the impact remains, mainly from the impactor's jacket, would heat up to high temperatures, boiling out volatiles, such as water, which explained the obvious lack of volatiles in the Apollo samples.

However, the analysis of Apollo samples did not end in the seventies – some samples were reserved for later research, and the technology did not exist yet. At the beginning of 2000, the analysis of lunar samples from Apollo 15 and 17 showed a surprising presence of water in small amounts. Since then, scientists have modified the gigantic impact hypothesis to account for the presence of water and other findings. Such modifications, however, cause that the gigantic impact hypothesis becomes more and more complex. The more extreme formation of the Moon appeared in 2017 with synesty hypothesis, a scenario in which a gigantic blow evaporated the entire early Earth, which later merged into the Moon and our present Earth. This scenario does not explain the water in Apollo 17 and 15 samples, but there are other new hypotheses. The many hypotheses with little impactfor example, it would allow water in the rising moon.

Land Syndrome (art)

The artist's concept shows a hot, molten moon emerging from a synestiaa huge swirling bud of evaporated rock that formed when objects of the size of the planet collided. Synesty is condensing, creating the Earth.
Sarah Stewart

In the coming years, new lunar missions will provide more information, perhaps enough to answer the age-old question of how the natural satellite of the Earth was created.


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