Mk Ultra was a program primarily aimed at mind control. It involved many different methods that were all extensively thought out and studied by psychologists. Much of it has been kept secret, but of what we do know, they tried physical torture of children, drugging people against their knowledge with LSD and other unknown drugs (leading to at least one suicide), and developing the psychological torture techniques on display at Abu Ghraib. Several times they tried to train assassins such as to kill Yasser Arafat, and I remember hearing somewhere that Sirhan Sirhan had connections to MK Ultra too. The point of the torture is not to get some information, it's to psychologically break and mold someone to their liking, like sleep depriving Bradley Manning until he agrees with them that he's actually Chelsea. It, like hypnosis, doesn't work on everyone, but it works on enough people that it can't be discounted. If the government had a secret space program, they'd be crowing to the skies about their advanced technologies. They'd be planting flags on Mars and talking about their brilliant jewish scientists that made it all possible. They'd have every reason to reveal it or parts of it, just as they have every reason to want people to think they have it now.