IGY Bulletin, Number 8, February 1958 - Satellite telemetry

This article in the Bulletin begins by stating that in order for non-recoverable satellites to be used for direct observations, telemetering systems must be used that record the satellite's observations, encode them, and transmit them to ground stations. Measurements can then be made in space rather than just from the ground, unhampered by the atmosphere.

Telemetry from satellites faced the extra obstacles of cost of the satellite, the need to record for long time periods, and the impossibility of maintenance. The telemetry system had to be of low weight, and have low power consumption. For the IGY program, one type of telemetry was done in real-time as data were collected, and another type used satellite-borne tape recorders. Volunteers equipped to make tape recordings of satellite signals were solicited to help with data retrieval and storage.

One gift for my bar mitzvah in 1963 was my first reel-to-reel tape recorder, as shown here.  I recorded some musical mix tapes from the radio (including My Girl from the Temptations) and exchanged letters-by-tape with a couple of friends in college. Last time I tried, the reels still moved, but the speed was not well controlled, and the playback was of poor quality. This tape recorder was almost IGY-era vintage!

The Bulletin article proceeds to describe details of telemetry systems used by IGY satellites that were collecting data on ultraviolet radiation, micro-meteoric particles, and cosmic rays. Much of the article is a little more technical than we need to go into.

The lead story in Popular Mechanics (1902-today) for the March 1958 issue was "Electronics and the IGY," the full text of which you can read here. I happen to own a copy of that issue. Below are scans of the cover and a photo from the article showing a telemetry recording system.

Scan of the cover of Popular Electronics, March 1958 issue

Scan of image in my copy of Popular Electronics. Caption: 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. 

As an aside, the term "satellite telemetry" has also been applied to a form of tracking of long-distance migrating animals used since the 1980s. After an animal has been captured and a tracking device has been attached, researchers can monitor movements of that individual for extended periods of time without having to recapture it. Satellite telemetry uses attached or implanted devices that communicate via radio signals to orbiting satellites, which give positional fixes on the device, and thus, the animal. This can replace older methods of tracking based on recapturing tagged individuals, or radio-telemetry which requires an observer to physically follow the tagged animal.

Speaking of animal migration, yesterday I made my nearly annual short-distance migration to the Middle Creek Wildlife Management Area, where tens of thousands of snow geese and tundra swans layover for a couple of weeks at this time every year as part of their incredible migrations back to the far north. For the day/time we were there, the number of birds in the lake were not not that impressive. I'm not sure if they had already left the area, or were just out feeding for the day.

We did see a nice group in chevron flight

The lake was sparsely occupied by tundra swans

I only have a few videos posted on YouTube. Here is maybe my first one, from 13 years ago, pretty low quality, showing some of the snow geese at Middle Creek:

IGY Bulletin, Number 8, February 1958 - A report on the United States Program

This IGY Bulletin article is a brief account of some activities in the U.S. IGY Program during its first five months (or about the first 1/4 of the 18-month IGY), from July 1 to Nov. 30, 1957. So it is effectively a review of things reported in the IGY Bulletin to date, some of which have been mentioned in previous posts. It is condensed from an article, "International Geophysical Year: A report on the United States Program," by Hugh Odishaw, Science, vol. 127. issue #3290, pp. 115-128, Jan. 17, 1958. I've mentioned Hugh Odishaw, executive director of the U.S. National Committee for the IGY, in a previous post. I own this press photo (stamped on the back  as UPI, 12/29/58) of him, taken at the end of the IGY.

You can download a pdf of Odishaw's article here. The backgrounds on some of the projects it describes have been provided in previous posts. Below I will bullet-point some of the highlights of the Bulletin’s 8-page article, using headings and subheadings from that article. 

Physics of the Upper Atmosphere

Solar activity

• The first major solar flare observed as part the IGY program was on 28 June 1957 (just before the official start of the IGY), leading to an Alert concerning the probability of solar disturbances.
• Measurements at the Mount Wilson Observatory in California found that the magnetic field at the sun's surface is about 10,000 times greater than that of the Earth.
• Magnetic observatories confirmed the existence of the equatorial electro-jet, a large but narrow electric current circling the Earth's equator high in the atmosphere.

Aurora and airglow

• The most complete synoptic maps ever of auroral displays were compiled, including the first confirmation that auroral displays at the north and south poles were synchronous.

Cosmic rays

• The "cosmic ray equator," where the cosmic ray intensity is a minimum, was found to deviate from the geomagnetic equator, perhaps due to cosmic ray deflections by extraterrestrial magnetic fields.
• With the first launch of an IGY test rocket on 5 July 1956 from Wallop's Island, Virginia, 83 rockets had been launched so far during the IGY, revealing atmospheric temperature, pressure, density, and ionization profiles.
• The launches of Sputniks 1 and 2 represented an extension of rockets' probing of the high atmosphere. 
• The U.S. was developing two types of satellites: test spheres for the testing of the Vanguard rocket system, and instrumented satellites to be later used with Vanguard and Jupiter-C rockets.

Earth's Heat and Water Regimen

Meteorology

• Synoptic meteorological maps of Antarctica were prepared for the first time, and continued on a daily basis.
• The South Pole Station, 10,000 feet above sea level, reported the lowest temperature ever recorded, -102.1 °F.
• Weather balloons were sent to altitudes of as much as 80,000 feet (15 miles) over Antarctica.
• Atmospheric ozone was measured in Antarctica for the first time, the beginning of a database that showed progressively decreasing levels of atmospheric ozone. In the 1980s, this depletion of ozone was attributed to the release of chlorofluorocarbon pollutants, garnering the 1995 Nobel Prize in chemistry for  Paul J. Crutzen, Mario J. Molina, and F. Sherwood Rowland.

Ozone ground measurements (black circles) starting at the time of the IGY, and later measurements above Antarctica (NASA)

• Carbon dioxide, "another minor constituent of the atmosphere which may play a role in climatic changes," was also measured in Antarctica. A summary of early analyses of carbon dioxide in Antarctic air collected in glass flasks at the South Pole between 17 May 1957 and 6 February 1976 
  were reported and tabulated in the publication Antarctic Carbon Dioxide Project, Report No. 5 (July 15, 1976), prepared by Charles D. Keeling, J. Alexander Adams and Carl A. Ekdahl of the Scripps Institution of Oceanography. This level has continued to increase in Antarctica, as it has worldwide. I think we can safely remove the qualifier "may" from the quote above.

The earliest carbon dioxide measurements from Antarctica (Keeling et al., 1976)

Glaciology

• In Greenland, the U.S. Army's Snow, Ice and Permafrost Research Establishment perfected techniques for drilling holes in the ice with hollow drills to obtain ice cores. The first hole drilled in Greenland in 1956 reached a depth of over 1000'. The layers of ice provide a stratigraphy of climate, precipitation, and volcanism
• Seismic studies in Antarctica were used to ascertain thicknesses of the ice sheet. Byrd Station, at an elevation of 5000', sat atop ice almost 10,000' thick.
• Oceanographic expeditions were used among other reasons for studying mean sea level. No mention was made in the Bulletin article about the sea level rise that has been a result of global warming.

Rise in sea levels since 1900. Pre-1940, glaciers and Greenland meltwater dominated the rise; dam projects slowed the rise in the 1970s. Recently, ice sheet and glacier melt, plus thermal expansion, dominate the rise. Tide-gauge data shown in blue and satellite data in orange. (NASA/JPL-Caltech)

• Geophysicists on Drifting Station A in the Arctic Ocean used seismic and gravity measurements to infer the floe had drifted over an underlying oceanic ridge which rose more than 5,000' above the ocean floor.

Earth's Structure and Interior

Seismology

• New earthquake seismographs were developed and deployed around the world, including ten long period seismographs that were especially able to detect surface waves with periods of 400 seconds, generated by only the very largest earthquakes. 
• Seismographs installed in the Pacific and Antarctic regions were to yield more complete patterns of global seismicity (which a decade later became critical for the theory of plate tectonics).
• Seismologists probed the thickened continental "roots" beneath the Andes Mountains of South America (a topic of isostasy to be blogged about at some point).
• The first successful gravity measurements were made on the open sea using a new model of gravimeter.

IGY Data

To handle the voluminous amount of data to be collected during the IGY at 2,000 stations by 10,000 scientists from 67 countries, three World Data Centers were to be established in the U.S., Europe, and the Soviet Union.

We can see that a number of strands of IGY research projects have endured, and have implications for critical issues that were barely considered at the time. That's how basic scientific research works, and why we must support it!

IGY Bulletin, Number 8, February 1958 - First sea surface gravimeter

We move on to the IGY Bulletin issue #8 from February, 1958. The download of this 20-page issue from the AGU website can be found here. The articles in this issue are:

1. First sea surface gravimeter
2. A report on the United States Program
3. Satellite telemetry
4. IGY satellite program notes
5. Thule neutron monitor station

Here I will summarize the first article. From an earlier post, gravity objectives of the IGY included:

• augmenting the global network of gravity measurements, especially in the Southern Hemisphere and polar regions
• better determination of the solid Earth's response to the tides
• enhanced measurement of gravity at sea

This article first reports on the first successful surface measurement of gravity in the open sea on Nov. 22, 1957, by J. Lamar Worzel of Lamont Geological Observatory, Columbia University. He used a Graf-Askania gravimeter developed at the Technical University of Munich by Anton Graf. The USS Compass Island provided a gyro-stabilized platform for this work.

In a basic physics course, we'd learn that the acceleration due to gravity at the Earth's surface is 9.8 m/s². However, because of the shape of the Earth, gravity varies on a longitudinally-averaged Earth from 9.7803267714 m/s² at the equator to 9.8321863685 m/s² at the poles, 0.5% higher, because you are closer to the Earth's center at the poles of our squashed (oblate spheroid) Earth. Gravity is also affected by elevation, local terrain, tides, moving measurement platforms (such as ships), and mass anomalies in the subsurface. Gravity surveys in geophysics are often used, after correcting for the other factors that affect gravity, to infer the nature of anomalous masses in the subsurface. Signals as small as 0.00001 m/s² (or about 1 part in 1,000,000 of the Earth's gravity field) are measurable with sensitive gravity meters (gravimeters) and can indicate significant "gravity anomalies."

Early gravimeters used on land were precision pendulum systems, since the period of a pendulum swing is related to the acceleration of gravity. Measurements at sea present a special challenge due to lack of stability and the addition of non-gravitational accelerations caused by the motions of the ship. In the 1920s, the Dutch geophysicist Vening Meinesz developed a system of two and then three balanced pendulums that were able to measure gravity underneath the sea surface by nulling out movement in the relatively quiet environment of a submarine. The later Graf instrument was basically a very sensitive spring-type balance that was able to measure gravity on the noisier platform of a ship at the surface. A measurement with the Graf could be taken in 9 hours and the data reduced in half a day, compared to two days and two weeks, respectively, for a measurement with the old pendulum systems. Today, measurements with modern gravimeters take a matter of minutes.

Seaborne gravity measurements are important since the oceans cover about 3/4 of the Earth's surface. The measurements to be made during the IGY were to fill major gaps in the extant world gravity database, especially in the polar regions and at sea, and then to meld the different national surveys together into a global grid.

As mentioned in an earlier post, the former German Democratic Republic (East Germany) issued a set of four se-tenant geophysics (but not IGY) stamps in 1980. The 20-pfennig stamp showed a modern gravimeter and how it might be used in delineating coal-bearing sedimentary basins. I just bought the block of stamps on eBay, from where the image below comes.

GDR block Scott #2146a, including the gravity stamp (Scott #2143), upper left

On my trip to Sarasota two weeks ago, I visited parks, the beach, played golf, ate good food, went to botanical gardens. I also perused the John and Mable Ringling Museum of Art (yes, the circus Ringling); I was not so keen on the old Italian art, but I liked the modern art, including this 1988 piece entitled Gravity, by Yuriko Yamaguchi:

And, on my last night, I went to the see a live performance at Circus Sarasota, including this gravity-defying balancing act by daughter-father team of Annaliese and Bello Nock.

What goes up, must come down, according to gravity!