Electronics and IGY
March 1958 Popular Electronics

Amateurs are aiding science's greatest international effort

By Mike Bienstock

Associate Editor

Scientists are in the midst of a concerted assault on the secrets of Mother Earth the likes of which have never before been attempted. The International Geophysical Year will not end until December 31, but by that time some 5000 scientists of 67 nations will have accumulated enough data to keep electronic computers clacking for years. The results, when they finally become known, are expected to increase the knowledge of the planet we inhabit by a thousandfold. We Earthlings are compressed between two oceans - the mass of atmosphere extending above us for 200 miles or more, and the mass of water, plumbed to a depth of more than 35,000 feet. We are familiar with just the fringes of these oceans, and even there the acquaintance is only nodding. Of the land area of our world, our deepest oil well has only scratched the surface. We barely have touched the edges of Antarctica.

It has been said that we know more about the stars, since we are able to stand off and take a good look at them, while here on Earth, so close to our subject, we grow cross-eyed trying to view the "big picture." Actually, it is suspected that we are off several hundred feet in our measurement of distances between continents.

Fields of Research. The IGY has planned, since 1954, to concentrate in one 18-month period investigation into the fields of aurora and airglow, cosmic rays, geomagnetism, glaciology, gravity, ionospherics, longitude and latitude, meteorology, oceanography, rocketry, satellites, seismology, solar activity and "World Days." The latter are periods of all-out concentration on one subject when there is sufficient warning of some unusual event in that field, for example, sunspot activity. 

Interior of aircraft instrumented for ionospheric research. The instrument in the foreground measures the heights of the layers in the ionosphere using vertical incidence pulses.

Most of the effort is being devoted to the atmosphere and the electrical phenomena which occur there.

Besides the professional scientists giving all their energies to IGY, thousands of amateurs volunteer time as observers to aid the effort. Project Moonbeam, organized to use the abilities of radio amateurs and others, has been vital in tracking the earth satellites, despite the fact that the observers were forced to make a quick switch from 108 mc. (the frequency originally decided upon) to 20 and 40 mc., which the Soviet Sputniks employed.

Tracking Systems. The primary system for tracking satellites by radio and recording their telemetered signals is the "picket fence" of Minitrack stations manned by professionals. The supporting Moonbeam program uses a simpler Mark II Minitrack system as well as a different setup, Microlock. Both use phase comparison techniques, and the equipment is simple enough to be built by amateurs.

Measuring telemetered data from rockets in flight at an installation in Manitoba, Canada. At the far left is a telemetry recorder which takes data from airborne rockets; in the center is the main recorder which puts data on tape; the ballistic camera master control is at the right.

In addition to radio tracking, visual and photographic observations are used by amateur groups.

While the satellites thrown into orbit by the Soviets and the United States are expected to reveal an astonishing amount of information in regard to the nature of the upper atmosphere, cosmic rays, auroras and the ionosphere, other devices mainly dependent on electronics are already contributing extensive data to the effort.

Scanning photoelectric photometer selects and measures the intensity of light too faint for the human eye and records its changes. This airglow camera is at Fritz Peak, Colorado.

For instance, radiotelescopes around the world are concentrating their antennas on the sun. Sunspots seem to be related to tremendous explosions on the sun that shoot out streams of charged particles, ultraviolet light and x-rays. Immediately after such "storms" on the sun, violent atmospheric disturbances occur. Very quickly short-wave communications fade, auroras burst forth in the northern and southern skies, cosmic ray intensity increases and the magnetic field of the earth shifts rapidly.

Strangely enough, not all sun "storms" cause these upheavals on earth. One of the things IGY is attempting to discover is the reason for this.

All during IGY, when such storms are detected, the world warning center at Fort Belvoir, Va., will be sending out alerts for special "World Days," during which scientists concentrate all of their energies on measuring whatever disturbances may occur. Up go "rockoons" (rockets launched from balloons) and Aerobee rockets fitted with delicate instruments to measure the intensities of x-rays, cosmic rays, ultraviolet radiation and such. A close check on the "shifting" of the E and F layers of the ionosphere is kept to determine the relationship of sunspots to such movements. Already a new layer of ionization, 12 miles below the lowest point, has been discovered. It was learned that this new layer was caused by solar x-ray emission associated with solar flares. Meanwhile, the normal layers of ionization, E and F, seem to remain stationary during a blackout, contrary to former opinion. It may be, therefore, that radio blackouts are caused by signal absorption in the newly discovered layer.

Radio transmitter with a 4000-mile range is part of the electronic instrumentation of the U.S. earth satellite.

Watch on the Mountain. A new instrument, the recording photometer, keeps watch on Fritz Peak, Colorado, to determine the change in the intensity of air-glow - a light so faint we can barely see it. This phenomenon is believed to come from some chemical reaction of oxygen, sodium and other ions in the D layer, about 60 miles up, and may be affected by solar storms.

Cosmic rays are getting the once-over for another reason: they give us an important clue to the character of the earth's magnetic field. Since they are charged particles, they are deflected by the earth's magnetic lines of force. Near the magnetic poles, where the lines are nearly vertical, there is little deflection, and therefore a greater intensity of cosmic radiation than along the magnetic equator, where the lines are close to horizontal. About 100 stations around the earth are measuring constantly the strength of cosmic rays, using two delicate electronic instruments, a neutron counter, sensitive to low-energy rays, and a meson "telescope," more sensitive to high-energy radiation. Collating the hundreds of thousands of readings of these instruments, scientists should be able to obtain a much better understanding of the shape and intensity of the earth's magnetic field.

Also in the tiny "moon" is a 48-channel encoder which receives and encodes data from other satellite instruments for transmittal back to the earth.

Another important study will be that of "whistlers," faint chirping and whistling noises discovered during the First World War. Back in 1950 it was learned that these noises are actually caused by low-frequency waves from lightning discharges, which follow the earth's magnetic lines of force from the point of origin, out into space, and back along the lines to the opposite hemisphere.

A huge antenna has been erected across a ravine in Colorado which is used to pick up these whistlers. A field station nearby amplifies them and records them on tape for future study. Another form of whistle is also being recorded there - the "dawn chorus." These noises, reminiscent of the pipings of frogs at dawn, are thought to be caused by streams of hydrogen ions at the edge of the atmosphere. Study may be able to correlate these noises with the intensity of solar storms.

With the advent of the forward scatter technique, which utilizes the ionosphere to bounce signals back to earth hundreds of miles away, engineers are anxious to learn all they can about this unreliable phenomenon so they can use it more effectively.

The National Bureau of Standards has set up test transmitters in South America to use the forward scatter technique across the magnetic equator. It is suspected that this method will be especially effective because the ionization layer theoretically should line up with the magnetic lines of force, thus making for more even scatter propagation. Again the radio amateurs assist in the IGY program, since many of them listen for these transmissions, especially in the western part of the country and in Mexico, and send their reports to the Bureau of Standards.

Auroras. Another important study is that of auroras. These intensely beautiful phenomena are believed to be set off by streams of hydrogen ions caused by solar storms. The ions are thought to react with the atoms of the upper atmosphere and make them glow like a fluorescent lamp. Some scientists had thought that auroras should occur simultaneously at both of the poles. This has now been established as a fact. Amateur astronomers have been recording the shape and intensity, as well as the angle above the horizon, of auroras in the upper northern regions. Concurrent investigations by meteorologists at the South Pole made the confirming study.

It is believed that auroras occur in day-time, although they can't be seen then. Therefore, observers near the auroral zone use sensitive radars to try to pick up reflections from the electron clouds which accompany auroras during daylight hours.

Although the IGY program will end officially Dec. 31, 1958, a good many projects will continue in operation. As a matter of fact, they may be prolonged indefinitely, especially those that are fairly inexpensive to maintain.

World data centers are being planned in the United States, the Soviet Union and other areas, in which digested results of the observations will be filed for scientists. It is not expected that such results will be put into usable form before 1965, but after that date science textbooks may have to be thoroughly rewritten because of IGY's results.