73-151 Nuclear-powered moon stations begin fifth year
NASA Johnson Space Center, Houston, Texas 77058
FOR RELEASE: November 18, 1973 (For November 19)
F. D. Williams 713/483-5111
RELEASE NO: 73-151
NUCLEAR-POWERED MOON STATIONS BEGIN FIFTH YEAR
Scattered across the face of the Moon, five experimental stations relay a steady stream of scientific information -- the energetic remnants of Man's first escape from his problem-plagued Earth.
Apollo 12 astronauts Alan L. Bean and Charles "Pete" Conrad Jr. placed the first of the automatic stations on the Moon during a four-hour exploration of the surface on November 19, I969. Today it begins its fifth year of operation.
With four other nuclear-powered stations scattered across the Moon's face, the Apollo 12 outpost reports its findings from a world where men no longer walk.
Nearly two dozen scientific instruments keep tabs on the Moon's pulse and respiration, expanding the wealth of knowledge gained by surveys made from orbit and from the surface in the first years of intense lunar investigation.
While seismometers register tremors caused by meteoroids, tidal forces, and internal changes in the Moon, other sensors record particles found in the extremely rarefied lunar atmosphere and measure the heat flowing from within the body. Yet another device detects the size and speed of micrometeoroids striking the surface.
Man's knowledge of the Moon has advanced markedly during recent years. Changes have come so quickly that few can remember our great ignorance in the days before the first spacecraft probed the Moon's mysteries.
Before the first flights to the Moon, our sketchy knowledge was based almost entirely on visual observation. With telescopes we could prepare rough maps of the Moon's near side, we could name its features, we could distinguish the dark plains from the rugged highlandso The size, mass, and shape of the satellite -- these were the limits of our firm knowledge.
Less than a decade ago, virtually nothing was known about the Moon's distinct chemical makeup, the geological structure beneath its surface, its age or evolution. No one could say for certain whether life -- even limited to the simplest viruses -- existed on the Moon. From the Earth, we could not tell whether water or oxygen were hidden beneath the surface, nor if they had perhaps been abundant long ago.
Whether the Moon had a magnetic field now or in the past was unknown. We had not yet learned to distinguish between craters produced by volcanoes and those left by meteoroids.
In the 1960's world of ignorance, speculation was king. Some reputable scientists argued plausibly that the Moon's plains were once washed by great oceans -- a theory that had led Galileo to the Latin name "mare, "or sea, for the broad, dark basins he saw in his telescope.
The first spacecraft to land on the Moon, another scientist warned, would sink beneath the dusty surface. The lunar rocks would burst into flame, some believed, when brought into the pure oxygen atmosphere aboard the Apollo lunar module.
Many people believed that the Moon had been pulled from the Earth's side, creating the Pacific Ocean.
A large number of scientists were confident that the Moon was [a] cold, dead body composed of material much like that of the Earth. Most believed that unlike the Earth, the Moon would not reveal the effects of any magnetic field present during its evolution -- a belief that seemed to be reinforced by the first crude measurements from space.
These myths -- once vigorous evidence of man's desire to understand something he saw but could not touch -- are now memorials to scientific progress.
Though the flights to the Moon were conceived to develop a new technology that would allow men to venture beyond the Earth, the scientific benefit they have brought is remarkable. We understand our own planet and solar system far better than a decade ago because we have pierced the mysteries of the Moon.
Continuing investigation of the Moon has produced findings that fill thousands of pages in scientific journals.
The Moon was created at the same time as the Earth, about 4.6 billion years ago. Although its origin is uncertain, scientists now have convincing evidence that the Moon was not pulled from the Earth to create the Pacific Ocean. Born long before thc Pacific, the Moon's chemical makeup is clearly different from that of the Earth's crust.
For the first 600 million years, the Moon was battered by large meteoroids. The battering culminated in a gigantic cataclysm, as a huge body smashed into the Sea of Rains, melting rocks and showering the Earth and Moon with debris.
The great collision produced a basin hundreds of miles across, the right eye of the Man in the Moon. No one can be certain now whether the whole solar system ran amuck then, or if the event was confined to the Earth-Moon system.
Since the cataclysm, the Moon's face has been scarred again and again by smaller meteoroids o Most scientists are now convinced that active volcanoes have not played an important part in the developments of the past 3 billion years.
Beneath the surface of the Moon, distinct layering can be detected -- a surprise to many scientists.
Where Apollo 12 landed, for example, about a kilometer (0.6 mile) or more of broken material lies at the surface. Below this is 20-25 kilometers (12-15 miles) of solidfied lava. The next 40 kilometers (24 miles) are of another type of rock, probably rich in feldspar. Still further down are rocks that have properties similar to the magnesium and silicon-rich rocks believed to exist in the region lying beneath the Earth's crust.
The Moon experiences tremors or moonquakes, most of which originate at a depth of about 800 kilometers (500 miles) beneath the surface. Most are caused by the tidal pull of the Earth and Sun, but some are the result of meteoroid impacts. Even the greatest moonquakes are far weaker than the powerful tremors sometimes felt on Earth.
Every year, earthquakes release a trillion times as much energy as the quakes occurring on the Moon.
Because certain seismic waves are transmitted by solid material, we can be certain that the Moon is solid to a depth of at least 800 kilometers, about halfway to its center.
Other seismic evidence indicates that the Moon is partially molten below 1000 kilometers (600 miles).
Just as the Moon is not entirely solid neither is it completely cold. Heat flows outward from the interior at a rate slight lower than that of Earth, but surprisingly large for such a small body.
Substances on the Moon were exposed to a weak magnetic field during its early history -- a field whose source is unknown. Because the remnant magnetism is weak, the first measurements from space failed to detect it.
The chemical composition of the Moon is unique. It is unlike certain meteorites believed to be similar in composition to the original material that formed the solar system, a finding that disappointed some expectations. Neither is it like the Earth. The Moon has less gold, carbon, hydrogen, nitrogen, free oxygen, lead, mercury, sodium, cadmium, and zinc at its surface than Earth does.
On the other hand, the mountains of the Moon are noticeably richer in aluminum and calcium than the Earth. At some dark plains sites, the surface is surprisingly rich in titanium.
Although the first astronauts to return from the Moon were carefully quarantined to protect Earth from microorganisms that might have lived on the Moon, we now realize that such precautions are unnecessary for visitors to the satellite.
The essential pre-cursors to amino acids, which form the basis of life on Earth, have been found in samples returned from the Moon, but neither amino acids nor primitive life have been detected there.
There is no water on the Moon, nor has there ever been. Not a drop of water can be found on or near the lunar surface. The famed "seas" of the Moon are far drier than the driest deserts on Earth. The Moon is so lacking in water that most iron found there shows no rust at all.
The Moon has so little atmosphere that it may be considered a vacuum. But particles are detected above the surface -- many of them produced directly or indirectly by the Sun, which radiates matter outward in a "solar wind."
Even our visual knowledge of the Moon has advanced tremendously. Cartographers have mapped substantial portions of both the near and far sides of the Moon in great detail using the photographs taken by Apollo mapping cameras.
Space flights showed us that the far side of the Moon is markedly different from the face we can see, with more rugged craters and highland regions, and fewer lowland plains.
While investigators continue to study the vast treasure of lunar samples and the continuing flow of data from the Apollo experimental stations, the thousands of pieces of knowledge gathered about the Moon are being combined in new ways to reveal ever greater secrets.
This synthesis of knowledge is expected to flavor the Fifth Lunar Science Conference scheduled to meet in Houston March 18-22, 1974.
Five experimental stations still pulse their messages through space despite years of searing heat and freezing cold -- a symbol of man's desire to reach beyond confining Earth, and a proof that he can do so.
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