First paragraph of the article:

In the wake of the 1963 Partial Test Ban Treaty, the United States launched a series of satellites under the name Vela (after a constellation in the southern hemisphere sometimes called “the sails” because of its configuration). The Vela satellites were designed to monitor compliance with the treaty by detecting clandestine nuclear tests either in space or in the atmosphere. The first such satellite was launched in 1963, the last in 1969. They operated by measuring X-rays, neutrons and gamma rays, and, in the case of the more advanced units, emissions of light using two photodiode sensors called bhangmeters (derived from the Indian word for cannabis). These satellites had a nominal life of seven years, after which the burden of detection was to be shifted to a new series of satellites under the Defense Support Program (DSP), equipped with infra-red detectors designed to pick up missile launches as well as nuclear tests. The Vela satellites, however, kept operating long past the end of their nominal design life and one of them, designated Vela 6911, detected an event on September 22, 1979, that has become a subject of intense interest ever since.

The American Academy of Arts and Sciences has published a paper with seven essays from leading scholars invited to respond to Scott Sagan's concluding essay in the Fall 2009 special issue of Daedalus on the global nuclear future. The paper includes Scott's original essay and responses by James M. Acton, Jayantha Dhanapala, Mustafa Kibaroglu, Harald Muller, Yukio Satoh, Mohamed I. Shaker and Achilles Zaluar.

As Leslie Berlowitz, CEO of the American Academy of Arts and Sciences, states in an excerpt from the paper's introduction:

"Renewed interest in arms control and restated commitments to the longterm goal of nuclear disarmament have clearly increased over recent years, most dramatically with President Barack Obama's April 2009 speech in Prague. With that change in focus comes an opportunity for the international community to rethink how Article VI of the NPT is traditionally interpreted and to move beyond the cycle of repeated complaints from the "have-nots" that the "haves" are not doing enough to disarm themselves and repeated retorts by the "haves" that they are already taking every step that is realistic or prudent. The promise of a different approach to the commitments made under the NPT forms the basis of the Scott Sagan's valuable article--"Shared Responsibilities for Nuclear Disarmament"...

"The differences in national perspectives and the differences in individual opinions about appropriate disarmament steps among the authors should not mask a commitment they all share. The contributors to this volume agree that new thinking and continued debate about how best to maintain momentum toward nuclear disarmament is to be welcomed. Only by seeking out, and taking into consideration, a cross section of views can progress toward the goal of a nuclear-weapons-free world continue...

"Their contributions serve to expand the discussion that was started by the original Daedalus article--and together they are intended to spark renewed policy debates about how best to pursue global disarmament, debates that will be prominent at the May 2010 NPT Review Conference in New York City and in the years following that important meeting."