'Early stages' is when the cancer is completely contained within the prostate. If it is detected when the cancer is entirely in the gland, the chance for full recovery is at its highest.
I really hate those books where the murderer turns out to be somebody you never heard of who pops up in the last chapter.
One of the most important things about the geology on the moon is your descriptions of what you see, comparing them to things that you've seen on Earth so that the geologists and the scientists on the ground would know what you're talking about; and then take pictures of them.