You know that mankind entered the Space 50 years ago already. Since then a lot of interesting discoveries were made though still I'm sure that mankind invests too little attention and resources to further and deeper Universe developing. It seems that governments of the most developed states engaged in confused priorities instead of consolidating energies on thorough scientific researches of the Space and constructing spacecrafts.
I think the first necesary point here is invention of new generation fuel type specially for space flies. Currently the fuel being applied for supplying rockets launching is very primitive, as provides little distance capacity and has poor energy output.
My idea is that spacecraft fuel must be reproductible out of substances that are easy to obtain, or even such fuel type should be extracted from vacuum. Or, spacecraft fuel may serve nuclear reactor of immense output rate but mankind still needs to get more skilled in dealing with such