[Question] Has government or industry had greater past success in maintaining really powerful technological secrets?

Con­text: As part of our efforts of work­ing on Open Ques­tions the LessWrong team has been reach­ing out to var­i­ous re­searchers we know and asked them about ques­tions they would be in­ter­ested in get­ting an­swered.

This ques­tion was given to us by Ryan Carey and some of the an­swers be­low are the re­sult of us try­ing to an­swer the ques­tion for a day on a pri­vate LessWrong in­stance, copied over to al­low other peo­ple to con­tribute and read what we wrote.