Zero G experiments: Even if we work under water or in a centrifuge we cannot get zero gravity on the earth. The only way to do that would be to bring a body with as much gravitational force as the earth, close to the earth. Zero G experiments have told us valuable things about the loss of calcium in the human body, how crystals from, how the human heart and muscles react with less stress on them, how it effects animals and several other things.
Exploration: when viewing anything from Earth we get interference from the atmosphere. Some wave links are even blocked by the atmosphere. The Hubble Telescope isn't so powerful; there are several telescopes that are more powerful. It’s the Hubble Telescope's position in SPACE that makes it so powerful. It can make further observations than any other telescope and it can see into wavelengths that an Earth bound telescope cannot. There are even plans to observe planets in other solar systems with Hubble.
Satellites: Communication and observation satellites have improved out life. Recently we just upgraded our weather satellite net so we can improve our forecasting abilities. That's how we predict hurricanes and are able to make a 5 day forecast, with more reliability. We need to see the entire picture, and thanks to the curvature of the Earth no earth-based system could see that picture. We can also see temperatures and get radar images, far more than just a couple of aerial pictures. How do you think we determined the global effects of El Nino? One satellite can observe and report on more areas than 1000’s of ocean buoys, and at a far cheaper price. Communication Satellites have improved all of our long distance communication. We use to have to run our communication lines from Europe to the US under the water. Electricity moves slower through a wire, than it does through air or a vacuum. When we communicate we can do it faster through a satellite. It is also a lot cheaper. If MTV wanted to broadcast to all the United States, without a satellite, then they would have to build a network of wires, and broadcast towers all across the United States. The major television networks and the AT&T built that structure so they could broadcast all across the US. It is a very expensive network to build and maintain. Satellites are cheaper, and if you want to add more bandwidth you just launch another satellite, instead of trying to string a wire under the Atlantic Ocean. With a satellite phone you can call anyone from anywhere in the world. Even on top of Mount Everest, or in the bush of Africa. Without satellites we would never know what the dark side of the Moon looks like. We wouldn’t have seen the moon’s largest crater, which helped to enforce the theory that a meteor collision destroyed the dinosaurs. We wouldn’t know what the planets and asteroids looked like. We would never have seen the surface of mars, much less landed probes on it. NASA has even sampled the atmosphere of Titan, which can only be done by going there. How would we determine if Mars had life or not? This is an important question, because it will give us a better chance of determining if life exists else where in the Universe. We have a satellite positioned between here and the sun in an orbit that matches the Earth’s speed. This early warning satellite tells us if a huge solar storm is coming. If we had it in operation last century then we wouldn’t have had the Great New York Blackout. We would have know a huge solar storm was coming and we could have taken steps to have prevented half the Eastern Seaboard and a lot of Canada from suffering a major black out.
Manned Space Flight: If we hadn’t visited the moon then we would not have known just how similar it is to the earth. Current theory says that our moon did not form like the other planets did. Instead it formed when a third body struck the still cooling Earth and blew off a chunk. Despite Russian efforts the only way we have found to bring rocks back from a planet or a moon is to go there and get them. Our probes can do some experiments, but they are greatly limited. With a rock on earth there is a whole lot more we can do to it to study it and determine its origins.
Side effects: Our improved ICBMs are the result of space travel, as well as our development in shooting those missiles down. Many products created were as a direct result to fulfill a need of the space program from Tang to Teflon. Freeze Drying is an excellent way to preserve material, especially coffee. It was invented to make astronaut food lighter and able to stay fresh longer. It is the technology that makes MREs possible. The US Military has been feeding its troops and many starving people off of MREs for years. They are lighter than C Rations so more can be carried, and they can be stored for a very long time.
GPS Navigation: It is all done with satellites. We could try and put up huge towers to replace it, but how do you put these towers up in the middle of the Pacific Ocean, or in China and Russia. GPS does everything from making our bombs and missiles into precision weapons to allowing your car to give you directions to you destination. It makes surveying so much easier, and we need to do surveying before we can start any major construction project.
The use of Aluminum: Our cars are lighter and stronger because we had to work on ways to make space ships stronger and lighter. This lead to things like aluminum block engines and crumple zones in cars that save peoples lives. We have done the same with aircraft, but the original idea came from space research.
Warfare: I don’t mean just weapons I mean the need for no more war. No sane nation in the world will attack us because we can see the attack from way off and can destroy the nation in only a few minutes. This has stayed Russia’s, China’s and North Korea’s hands from attack the US. Star Wars may have been a dream, but it was important enough to make the Soviet’s nervous. With a missile defense system, most of which would HAVE to be space based, no country in the world could attack the US, or any of its allies. Sure, terrorists are hitting us, but suicide attacks are attacks of desperation, where your warriors die, and they still might not be able to carry off the attack successfully. The Gulf Wars are probably the last conventional wars that will ever be fought.
NASA has also contributed to other programs. The first advanced fighter designs came out of NASA programs. The SR 71 Blackhawk was a NASA program. NASA has done high altitude atmospheric and weather tests. NASA has created the world’s fastest plane. They are now testing the first craft that can go hypersonic speeds.
These are just the few things, off the top of my head, just a few reasons why NASA and the space program have changed our lives, beyond more than a few aerial pictures.