If you say that something isn't rocket science, you mean that it is easy or obvious. It isn't rocket science to figure out that you will sell more sweets if you put them where small children will see them. People should be able to fill in the forms themselves — this isn't rocket science. Note: You can use expressions such as it doesn't take or you don't have to be a rocket scientist to point out that something is very easy or obvious. It doesn't take a rocket scientist to figure out why he's so angry. You don't have to be a rocket scientist to work it out. Note: The expression rocket scientist, meaning `very clever person', is used in various other structures. Now I'm no rocket scientist, but even I could see those figures looked way too high.