No, I believe that the thread is related to NASA's exploration of Pluto, not about USA's defence spendings. If they do something pointless like sending a squadron to Antarctica, and someone makes a thread on that accomplishment, then I'll raise the issue of mal-expenditure there as well. I commented in relevance with the topic. I'm not a military expert, so I cannot explain with confidence exactly why America spends the highest amount on defence, but there are some facts that we know, like America being the sole superpower in the planet for the last 25 years or so, and some of the factors which I mentioned above (which are facts as well), came about as a result of that, others spontaneously... all these compel America to have a very high defence budget. I'm not saying that America cannot take some money away from that and put it towards the welfare of the world's poor; I'm saying that the money that is spent on defence has much bigger necessity than the money spent on space exploration, especially so for planets other than Mars, which wouldn't help us in any way.