May as well get this out of the way: I don't hate NASA, and when it comes to bad departments, NASA is pretty low on the list. However, it IS quite wasteful and most of its benefits would be present were it simply a part of the DoD.
Now, back to the topic at hand,
Didn't I just cover satellites by the way? They weren't invented by NASA, weren't first used by NASA, and would exist in the modern day either way.
So the DoD would just get the satellites into space by strapping them onto Peter Pans back?
Or would they maybe need to develop rocket propulsion along the way... i.e. NASA.
This argument feels like watching a monday morning quarterback argue that he would be a better coach then the head coach of an NFL team. Sure the other guy might have worked his entire life in the sport, know all the players and the competition, is entirely versed in the minutae of what he does and have the sort of skill and intelligence that could get him a well paying job in an entirely different industry if he was so inclined. But any time he makes a bad call you are going to think you are better then him because you happened to make the right guess before the fact... or after.
You do realize that Bell Laboratories was producing satellites as early as
1962 right?
Yes, they reached space via a NASA rocket, but then were NASA not making rockets then Bell and other companies would have had a pretty good reason to start trying to make their own rockets; it wouldn't be terribly unrealistic either, its not like the aerospace engineers, astrophysicists, etc would vanish if not hired by NASA (and indirectly crowding out any alternatives).
NASA's current budget is 0.47% of the total. Which is about one third of the budget of homeland security.
The DoD is 19%. And over the past ten years has been increased by 150%
Get rid of Homeland Security, then. That's a positively terrible department. While you're at it, the DoD definitely needs to be cut down significantly (Which I said earlier): the US doesn't need a gigantic standing army and a military presence across the world. As with above, I wouldn't say NASA is a terrible department, just a wasteful one.
FYI, the modern version of the internet was developed by a scientist CERN, in order to distribute data from one of their previous particle arcelerators. They only thing DoD did was connect some university computers, while the CERN's version actively transmitted and relayed data. So you can't say they invented it, as others woud have done it anyway, and in fact, did it better than them. Besides, the DoD defense has wasted tons of money too.
As for things being improved upon. In a way you can say anything is an improved version of something else. Most things NASA, or any other space organization did, are imrpovements on other technologies, but that are things that wouldn't have been done on Earth. Examples include various medical technologies (Research into Caisson disease, osteoperosis, human reaction to different pressure, heart related diseases), sattelite technology, firefighting equipment, material science, ...
But really, at the moment NASA is wasting tons of money because they constantly have to cancel projects to fulfill congressional mandates (Space Launch System, for example) and to keep some other projects alive. Doubling their budget would allow them to actually do something again.
Oh, I'm not debating that NASA has made lots of scientific discoveries. It definitely has. But has it produced enough to really be worth it?
The vast majority of its discoveries very well could have been done on Earth, and it produces just as many useless products, failures, and so on as it does worthwhile things. After all, NASA has, from 1962 to today, cost around $750,000,000,000 (adjusted for inflation and rounded, of course). Would you say NASA has produced enough to be worth three quarters of a trillion dollars?