How many complex machines (or complex anything) are going to work first time? Most things require an iterative loop of testing, fixing and refinement. The tro

How many complex machines (or complex anything) are going to work first time? Most things require an iterative loop of testing, fixing and refinement. The trouble with landing on another planet (with different gravity, atmospheric density, etc) is that there's no real way before you get there, therefore first attempts are extremely likely to fail.