Televising the Moon
October 1964 Radio-Electronics

October 1964 Radio-Electronics [Table of Contents] Wax nostalgic about and learn from the history of early electronics. See articles from Radio-Electronics, published 1930-1988. All copyrights hereby acknowledged.

In this October 1964 issue of Radio-Electronics magazine, editor Hugo Gernsback writes about the historic feat on July 31 of that year, where NASA lunar probe Ranger 7's RCA-designed television cameras successfully transmitted the first close-up televised pictures of the moon's surface to Earth after six previous failed attempts. The unmanned spacecraft, managed by NASA's Jet Propulsion Laboratory, traveled 240,000 miles through space over 68 hours to capture 4,316 still images with its six high-resolution cameras. These images provided crucial information for future manned lunar explorations, revealing that the dust layer on the moon's surface is likely only 2 to 12 inches deep, and showing small craters down to sizes of three feet. The success of Ranger 7 marked a significant advancement in lunar exploration technology, paving the way for further unmanned missions and eventual manned expeditions to the moon.

Televising the Moon ... What Are the Requirements of Future Lunar Landings? ...

By Hugo Gernsback

On July 31, after 6 previous Ranger attempts to reach and televise the moon had failed, the RCA-designed television cameras of Ranger 7 sent to earth the first close-up televised pictures of the moon's surface. This historical feat was accomplished by the Jet Propulsion Laboratory of the National Aeronautics & Space Administration (NASA).

The unmanned Ranger 7 had traveled through 240,000 miles of space to hit the target, the moon, 2,160 miles in diameter, in a voyage that lasted 68 hours. Starting at about 1,200 miles from the moon, and for the last 17 minutes of their flight, the six high-resolution cameras took 4,316 still pictures with a 1,152-line scan. First two wide-angle cameras started operating. Four narrow-angle cameras, scanning a smaller area, began operating.

The vidicon signals then were converted to FM signals to earth by 260-watt transmitters at frequencies of 959.52 and 960.58 mc.

The signals were picked up on earth by two 85-foot Goldstone antennas, 150 miles northeast of Pasadena, Calif. They were recorded in two ways: optically and magnetically on tape.

The 382-pound television system was designed primarily to give a series of close-up views of the moon's topography to help find a suitable site for future manned lunar explorations.

During the last few seconds of Ranger 7's flight, when it was approximately 1,000 feet from the moon, the last television picture - or rather, an incomplete picture - was taken. This then was the closest picture obtained. All it showed were some small craters down to sizes of three feet. In the words of Dr. Gerard Peter Kuiper, of the University of Arizona, who headed the Ranger 7 team of the Jet Propulsion Laboratory, "the best resolution (of the picture) obtained is approximately one foot and a half."

To the nonastronomer and the nonlunar scientist, the television pictures, excellent as they were, and 1,000 times clearer than anything man ever had up to now, seem puzzling at first. It should always be remembered that the closest picture of the moon's surface taken by Ranger 7 is still 1,000 feet up. And how much detail can one see of the 5th Avenue pavement from the 80th floor of the Empire State Building? Very little. Not only that, but at such a height there is very little perspective of the street.

While all NASA scientists are highly elated over the Ranger 7 results, it will be many months before the 4,000-odd photographs are finally deciphered and evaluated.

So far it seems that one of the most important lunar puzzles has already been partly solved - the deep dust problem. According to NASA astronomers, the dust layer probably is only 2 inches to 12 inches deep - not deep enough to prevent a successful manned landing. Nor are the small pits, the little craters, dangerous enough to prove disastrous.

Previously, Dr. Kuiper said it had been speculated there might be a thick, potentially dangerous layer of dust on the surface. But the evidence of the latest pictures "requires us to assume that the surface is hard."

"I am willing to bet that if you walked on the moon it would be like crunchy snow," he observed at a briefing conducted for Congressmen in Washington on Aug. 6.

It is now certain that there will be many other Ranger-like unmanned moon shots before manned exploration expeditions are attempted.

Nor will we have further crash landings, unless they are wholly accidental. Today lunar technology has advanced sufficiently to soft-land our capsules without shock and consequent damage to their dozens of vital exploration sensors.

Such future capsules will have a variety of television cameras for close-ups of the immediate lunar vicinity, as well as photographs of the earth from the moon. All sorts of temperature measurements will be taken, not only of the moon's surface but several feet below, during regular intervals. The results will be radioed every hour to earth scientists.

There will be regular seismic tests exploring the moon for expected earthquakes, due chiefly to disturbances induced by the tidal effects of the earth's gravitational pull. All these effects will be radioed to earth.

The true composition of the moon's crust will be analyzed by chemical-physical robots and reported at intervals to earth monitors.

What are the electrical effects on the moon's surface of the wide fluctuation of its temperature, from plus 200°F to minus 250°F? Our future Rangers will supply the answer. We should always remember that the moon, having no atmosphere, is in a perfect vacuum, hence the wide temperature fluctuations may give rise to cathode-ray currents near the surface, which might prove annoying to explorers.

How often do micrometeorites strike a given square yard on the airless moon? So far we do not know. But our robot-equipped lunar capsule will radio the answer to earth to the satisfaction of our scientists and our later lunar explorers.

What about the effect of solar winds on the unprotected moon's surface? We are now in the quietest part of the solar cycle. What will be the effect on the moon when we go into the high-activity part of the sunspot cycle 3 or 4 years hence? As yet we do not know if such a period is dangerous to lunar explorers. But our moon-capsule robot will give us the answer, before we get there.

Let us never forget that the physics of the moon environment and those of the earth differ vastly. We cannot take chances with live men on the moon until we know for certain.

Finally, before too long we will probably change our ideas on how to soft-land our sophisticated Ranger-like robots. One idea is shown here. Instead of using compression springs on our robot capsules, now advocated by many designers, we could use large-20- to 30-foot-sturdy polystyrene or other plastic balloon-like spheres, equipped with retrorockets. On the airless moon they could not of course float. They would be automatically gas-inflated before landing, hence would settle slowly with little shock that might damage the multiplicity of the capsule's delicate instruments.

- H.G.