from the FAS Project on Government Secrecy
Volume 2011, Issue No. 62
June 28, 2011

Secrecy News Blog:


On May 26 Archivist of the United States David S. Ferriero announced that the Pentagon Papers, the famous history of the Vietnam War, had been formally declassified and would be released -- except for eleven words that remained classified. But then on June 13, the Papers were published in full with no redactions at all.

What happened? It turns out that the mysterious eleven words had already been published 40 years ago, making their continued classification moot.

Staffers at the Lyndon B. Johnson Presidential Library discovered on June 3 that "The full text of that page [containing the eleven words] was released in 1971 [by the House Armed Services Committee] in what appears to be an officially declassified copy," according to email correspondence released this week by the National Archives under the Freedom of Information Act.

In other respects the House Armed Services Committee edition of the Papers was "heavily redacted," officials noted, but it did contain the eleven words.

Given the fact of their prior disclosure, any attempt to keep them classified now would surely backfire, they reasoned.

"The researcher who is most aggressive in pursuing the PP [Pentagon Papers], John Prados [of the National Security Archive], will most likely find the 'declassified' occurrence of the page pretty quickly. So please advise everyone that if they insist on maintaining the redaction, Prados will likely scope out the 'declassified' page very quickly. As you can tell by his NPR appearance [on June 3], Prados will parade this discovery like a politician on the 4th of July," wrote Alex Daverede of the National Archives.

This argument was persuasive, and the proposed redactions were deemed to be "no longer appropriate." But neither the classifying agency nor the now restored eleven words themselves were publicly identified. Sheryl Shenberger, the former CIA employee who leads the National Declassification Center, told her colleagues somewhat peremptorily that such disclosure was "unnecessary."

"I think we can all agree that it is unnecessary to provide any further insight into what was originally considered for redaction or which agency or agencies were suggesting those redactions," Ms. Shenberger wrote. "It should be enough to announce that we... are delighted to have determined that we can release this historic document in full."


Fifty years ago this week, on June 29, 1961, an electrical generator driven by nuclear energy was launched into space for the first time.

The SNAP-3 radioisotope thermoelectric generator (RTG) powered by the natural decay heat of plutonium-238 provided a minuscule 2.7 watts of power to the Navy's Transit 4A navigational satellite, which was placed in orbit around the Earth at a mean altitude of 930 kilometers. The event was commemorated in this advertisement for Martin Marietta, as the device's manufacturer was then known, which appeared in the December 1962 issue of Astronautics magazine (thanks to Gary L. Bennett):

Since that time, plutonium power sources have enabled a series of ambitious missions into deep space that may rank among the grandest adventures of all time, extending human cognition into domains that were previously accessible only by imagination. Voyager 1 and 2, for example, twin RTG-powered probes which were launched in 1977, are now on the threshold of becoming the first spacecraft to leave the solar system and to enter interstellar space.

"The men and women involved in Voyager did something that is absolutely the equal of Magellan or Columbus or any of the great explorers of terrestrial discovery," said project contributor (and FAS sponsor) Ann Druyan. She and Voyager project scientist Ed Stone offered "Perspectives on More Than 3 Decades of the Voyager Mission" in an article by Randy Showstack in the May 10 issue of Eos, the weekly newspaper of the American Geophysical Union (scroll down to the middle of the first page):

Unfortunately, the plutonium 238 power sources that are used to power these missions are not only expensive, they are dirty and dangerous to produce and to launch. The first launch accident involving an RTG occurred as early as 1964 and distributed 17,000 curies of plutonium-238 around the globe, a 4% increase in the total environmental burden (measured in curies) from all plutonium isotopes (mostly fallout from atmospheric nuclear weapons testing).

A plutonium fueled RTG that was deployed in 1965 by the CIA not in space but on a mountaintop in the Himalayas (to help monitor Chinese nuclear tests) continues to generate anxiety, not electricity, more than four decades after it was lost in place. See, most recently, "River Deep Mountain High" by Vinod K Jose, The Caravan magazine, December 1, 2010:

A good deal of effort has been invested to make today's RTGs more or less impervious to the most likely launch accident scenarios. But they will be never be perfectly safe. In order to minimize the health and safety risks involved in space nuclear power while still taking advantage of the benefits it can offer for space exploration, the Federation of American Scientists years ago proposed that nuclear power -- both plutonium-fueled RTGs and uranium-fueled reactors -- be used only for deep space missions and not in Earth orbit.

Although this proposal was never officially adopted, it represents the de facto policy of spacefaring nations today.

The next RTG enabled space mission, the Mars Science Laboratory (MSL), is scheduled to be launched from Cape Canaveral between November 25 and December 18 of this year. The MSL rover, known as "Curiosity," will be fueled with 4.8 kilograms of plutonium dioxide. It will be, NASA says, "the largest, most capable rover ever sent to another planet."


Secrecy News is written by Steven Aftergood and published by the Federation of American Scientists.

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