- "It is thought[by whom?] that national security reasons delayed the disclosure to the media." Ludicrous. More realistic is they were afraid of negative media

- "It is thought[by whom?] that national security reasons delayed the disclosure to the media." Ludicrous. More realistic is they were afraid of negative media coverage and protests about the potential public health hazard to their people. In the US, NASA goes to extreme lengths to qualify their space radioisotope devices, their survivability and how they fail in a failed rocket launch or unplanned atmospheric reentry. All of which is transparent to the public, and to independent review. There's AFAICT the opposite of such transparency and accountability here. It's not clear at all what degree of risk this (at-the-time secret!) radioisotope launch had, how the containment device was engineered and what potential (secret) flaws it could have.