This argument comes up in these discussions quite frequently. Yes, some of the research done for purpose A ends up being able to be re-used for purpose B. It

This argument comes up in these discussions quite frequently. Yes, some of the research done for purpose A ends up being able to be re-used for purpose B. It is not a compelling argument because: 1. We have no way of predicting how much or what technologies will be the useful ones or what they will be useful for 2. Any other scientific or engineering endeavor we do instead of sending humans into space, including a massive increase in building/sending robots into space, will have the same potential side effects