I wrote a very detailed reply for this with lots of sources, but deleted it because it would only invite more questions that you can find out the answers to yourself. Really what you are asking requires several books worth of information to fully explain.
Basically just read everything on Wikipedia about DARPA, NASA, CIA satellites, the NRO, the Apollo missions, Sputnik, Voyager 1 / 2, the Curiosity rovers, KH-9, KH-11, Hubble, etc. then come back and criticize NASA if you still think that they are not doing their job properly.
You have the answers to all of these questions and more at your fingertips via Google.
NASA has another Curiosity rover, but the cost/benefit of sending it to Mars isn't worth it in their expert opinions.
Basically just read everything on Wikipedia about DARPA, NASA, CIA satellites, the NRO, the Apollo missions, Sputnik, Voyager 1 / 2, the Curiosity rovers, KH-9, KH-11, Hubble, etc. then come back and criticize NASA if you still think that they are not doing their job properly.
You have the answers to all of these questions and more at your fingertips via Google.
NASA has another Curiosity rover, but the cost/benefit of sending it to Mars isn't worth it in their expert opinions.