It's interesting that you believe that missions like this must be justified by short term benefits. These missions are very fortunately not about short term ben

It's interesting that you believe that missions like this must be justified by short term benefits. These missions are very fortunately not about short term benefits. One of the initial motivations for this mission was to learn more about our solar system's origins by studying a comet up close. Many engineering challenges were also overcome in the process, which will lead to positive side effects for future space missions and related areas, but one of the primary scientific questions this mission attempts to answer is "why is our solar system the way it is?" Answers to that question will likely help us better understand our place in the universe, and possibly shine a light on other solar systems as well. Maybe even give us a better idea how likely we are to encounter life in other solar systems, and what that life might be composed of. Ironically, compared to questions of cosmic significance like these, short term concerns like treating present diseases or improving the current economic environment are petty and irrelevant by comparison. These are issues that science and government can tackle on earth, and issues where throwing more money at the problem doesn't always help. It is a fallacy to think that because space travel requires money, that earthly needs will go unfulfilled. It's deeply short sighted, in fact. Your comment seems to be rooted in a deep misunderstanding of the nature of science. Science does not proceed by first devising a list of improvements to human wellbeing that will result from an experiment (though the grant application process in universities sometimes encompasses this task--with a lot of handwaving as a result). Science is about expanding our sphere of knowledge. By definition, we don't know what will result, or if it will have a positive impact. But we are trying something that has never been tried before, which is deeply interesting, and which has the potential to greatly expand our knowledge of the universe. Science is fundamentally a research activity: you can't know in advance what you will find. Asking what we will find before performing the experiment is pointless. The "might find" category for a mission like this is enormous, however.