You carry your expectations to a book, and this one was a disappointment to me. This book, in my view, offers a sophisticated version of hero worship. But, while showing many of the foibles of the characters, it is worshipful and indeed, facile myth generation. You get a bunch of you-are-there style descriptions - the kind of light stream-of-consciousness that made Wolfe famous as a hip young beat journalist - and they are fine as far as they go, but at least for me, I felt there is far too little substance behind it.
In spite of Wolfe's somewhat cynical veneer, the characters fall into some pretty simplistic stereotypes. You get the tough, natural aristocrat, Chuck Yeager, the real yet unknown superstar, and then you get the media-sensation astronauts, who are promoted for political propaganda reasons. Thus, there is John Glenn ("the clean marine") and a host of other less colorful characters. I did not feel I got to know much about them. Glenn, whom I worked for in the Senate 20 years ago, comes off as the most boring of straight men, which I don't think encompasses him well at all.
Then there is the period of history in which it all takes place, the Cold War. Wolfe offers nothing much of interest about this frightening period of technological competition between the US and USSR. I felt it was just kind of a useful background for Wolfe. This stands in stark contrast to Wolfe's wonderful Electric Coolaid Acid Test, which really plumbed a lot of the 1960s psychedelic spirit - that was why I expected so much more, I suppose.
I would recommend this as a fun read, but not much beyond that. It is strictly throwaway and does not demand much concentration or stimulate the reader to dig deeper elsewhere, which for me signals a failed reading experience.