"Some things may have been tried before their time, but if these things don't violate the laws of physics they are likely to prove possible the next time around. Engineering is a series of failures with an occasional success. At least the kind where you are really looking at new technology. You tend to try things. You try things that are extrapolations of what has happened before. A lot of them don't work. Occasionally, you hit one that does. That's the way we make progress. Failures are not something to be avoided. You want to have them happen as quickly as you can so you can make progress rapidly. But, I've known technical people who are very competent but who would avoid doing a critical experiment. They would kind of work around the problem and do the things where the results were relatively straightforward, but they hated to do that experiment that might tell if their whole approach was right or wrong. And these people were relatively nonproductive. Then I've known other people who weren't perhaps as bright as the ones that worked around the problem who jumped right at the heart of the matter. They turn out to be the most productive. So my single piece of advice is don't delay making the critical test. That's the one that will tell you if you are right or wrong and where to go next."