Letters

More hot properties

Sarah Horowitz's article, “Hot Properties,” in the May/June Bulletin, tells some stories about collecting “Vaseline glass”—otherwise known as “uranium glass.”

In addition to its use in calibrating radioactive counters, as Horowitz mentions, uranium glass was also used by glass-blowers in “graded seals,” which were needed for sealing metal electrodes into glass apparatus. Graded seals were necessary to provide a gradual transition of thermal expansion coefficient between Pyrex, which was the glass of choice for most apparatus, and tungsten, which was the typical electrode material. Uranium glass was one of several types of glass that could serve. Uranium-glass graded seals could always be recognized by their yellow band.

When I was a student in the 1940s, Columbia University's chemistry department had a very skillful glass-blower who made numerous pieces of apparatus for several departments, as well as for the laboratory where I was a student.

He told me that he had once prepared several pieces, using uranium glass for graded seals. They turned out to be an utter failure—his customers had not told him that the pieces were to be used in Geiger counters. It took them a long time to realize that the source of the high background radiation they recorded was the glass tubes themselves.

J. Gregory Dash

Seattle, Washington

Curious clusters

I found LeRoy Moore's report on standards of radiation exposure (“Lowering the Bar,” May/June Bulletin) to be very interesting. At Med-act we have been concerned about the possible role of low-dose radiation in causing clusters of acute lym-phocytic leukemia in children. In Europe, four such clusters have been known, several for as long as 20 years. Three are near the nuclear reprocessing sites at Sellafield and Dounreay in Britain and Cap de la Hague in France. The fourth is in west Berkshire, where plutonium for nuclear weapons is machined.

On standard models of radiation hazard, public exposures in these areas are too low to cause leukemia, and the clusters are currently ascribed to an unusual reaction to an infective agent, presumably a virus, related to population mixing. The cause is thought to be either an uncommon virus, or an atypical response to a common infective agent.

However, as Moore notes, the “bystander effect” and other forms of what is now known as “genomic instability” raise profound questions about the effects of low-level radiation. Such effects are more likely to occur with internal exposure to alpha-emitters such as plutonium, which is retained in both bone and testis. Radiation-induced genomic instability has recently been shown to be passed through more than one generation in experiments on mice, and leukemia arises in the bone marrow.

It is well known that interactions between some therapeutic agents that are safe when given alone can be devastating when they are administered together. Accordingly, we have suggested the possibility that low-dose radiation, particularly from internal alpha-emitters enhanced by genomic instability, could be synergistic with an immunologi-cal reaction to infective agent(s) in causing clusters of leukemia. This possibility should be taken into account in formulating standards of radiation protection and in deciding on policies for handling radioactive materials.

OPEN IN VIEWER

Douglas Holdstock

Medact London

Flying below the clouds

James Marquardt's article, “Open Skies: Not a Moment Too Soon” (January/February 2002 Bulletin), describes very precisely the treaty's history, relevant provisions, and current political issues.

Marquardt's major critique with respect to the usefulness and efficiency of the treaty today and in the future centers around the argument that “better intelligence is already available from high-resolution satellite imagery operated by commercial remote sensing providers and as a result of national technical means. In contrast, Open Skies seems quaint.”

We question this conclusion for two reasons:

First, the resolution of the photographic and thermal infrared cameras used in Open Skies is unmatched by any existing or proposed commercial imaging satellite. Space Imaging is licensed to launch a 50-centimeter resolution sensor, still above the 30-centimeter resolution under Open Skies. Moreover, Open Skies images are routinely taken in stereo mode, which provides much enhanced power for object identification through height determination. It would be extremely difficult to reach the 50-centimeter resolution of Open Skies thermal infrared images from space. It would require mirrors of 5 meters in diameter or more. No commercial satellite provides thermal images at 10-meter resolution!

The author is, however, correct in assuming that the 3-meter radar image resolution under Open Skies will soon be outdated—by a commercial radar satellite of 1-meter ground resolution developed by the German Aerospace Establishment (DLR). Russia also has the technical ability to build high-resolution satellites, and the French reconnaissance satellite Helios II may reach the 30-centimeter resolution class.

Second, it is true that the United States acquires sufficient and better intelligence from its national satellites. But are data from these satellites available to all parties to the treaty? Data from national reconnaissance satellites are in general highly classified. They are not routinely available, for instance, at the Organization for Security and Cooperation (OSCE) in Vienna. They are of little use with respect to the aims of confidence building and crisis management in a multilateral context like the OSCE or the United Nations.

The treaty's sensor suite of highresolution stereo imaging and thermal imaging at night, and its ability to underfly dense cloud cover, makes Open Skies information-gathering technically superior to satellite data accessible to most treaty members.

The political context of the treaty has changed, of course, since 1992. The issue of asymmetric flight execution (that most parties want to overfly Russia, with no mutual overflights of NATO member states) must be addressed. And tensions between most parties have been reduced. But important areas of concern remain in which the Open Skies approach can unfold its potential for confidence building and conflict management. These include Russian concerns about NATO expansion, relations between Russia and the Baltic states, Russian concerns about the U.S. missile defense buildup, and the Balkans, Caucasus, and Central Asian crisis regions.

If the Open Skies Treaty is outdated, why did Finland and Sweden hasten to join after it entered into force on January 1 of this year?

The treaty's potential goes far beyond reconnaissance. Opening one's own full territory to foreign monitoring overflights sends a powerful symbolic signal. There is also the very important dimension of extended cooperation of joint teams during flights and the sharing of image data. The author is invited to join one of those flights in order to experience that dimension.

Ernst Britting & Hartwig Spitzer

Hamburg, Germany

Colonel Britting, a former German Air Force fighter pilot who earned his wings at Sheppard Air Force Base in Texas, is in charge of the Open Skies section at the German Armed Forces Verification Centre at Geilen-kirchen. Professor Spitzer, a physicist, is head of the Center for Science and International Security at the University of Hamburg, Germany.

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James Marquardt responds: Ernst Britting and Hartwig Spitzer, distinguished experts on the technical merits of the Open Skies Treaty, bring to light important information overlooked in my essay. They are correct that the resolutions of the photographic and thermal infrared cameras found in the treaty exceed those that are currently available in the commercial marketplace. They also correctly indicte that, under certain circumstances, Open Skies data may be superior to data derived from national technical means, and this data is adequate to achieve the goal for which the treaty was created— namely, confidence building.

Nevertheless, I continue to disagree with Britting and Spitzer on the issue of the political significance of the treaty. The original proposal of 1955 was part and parcel of the growing distrust between the United States and the Soviet Union. American statesmen had no illusions about the prospects of an aerial surveillance regime: Eisenhower proposed it because he and others expected the Soviet Union to reject it. Soviet leaders maintained that unrestricted overflights would simply exacerbate tensions and therefore opposed it.

The Open Skies Treaty, in contrast, is the product of the dramatically transformed international political environment that emerged a little more than a decade ago. I argue that the treaty is antiquated because the use of mutual overflights as a confidence-building measure has Cold War tensions as its point of reference. It is ironic that openness proved elusive when Cold War tensions ran high and now stands to flourish in a recently transformed world where tensions are quite low. In years to come, the treaty may well function as a pillar of a new international security architecture, as its proponents suggest. I certainly hope so. Yet it is possible that this pillar—and the architecture it supports—may yet be toppled by a new, unfavorable international climate.

In any case, I would be delighted to have the opportunity to participate in an observation flight with the authors.