the oxcart would sometimes almost stalled.is how slow it had ago. >> somebody in the audience is why was the government prompted to declassify this and provide great stuff for your book? >> that is an interesting question. they didn't declassify all this stuff. they declassified the oxcart in 2007 and are don't know why. i have asked some people at langley why and they have different answers, none of which answer the question. because if you are trying to keep a base secret it would make sense not to declassify one of the major programs there. but that is how i was able to speak to the original source, that is how high was introduced to the next and the next and the different sources who make up the narrative of my book and to whom i am very grateful because it was an honor and privilege to be able to talk to these men who are really a group of cold war heroes. scientists, spies, engineers, physicists who were only known among themselves and now i think in reading the book you are able to have a really interesting window into