I was wondering about sketching in the cave. I know pencils have their merits due to being able to erase mistakes........but I see that places also sell the space pens (they write upside down) where they sell survey paper and other surveying supplies. Has anyone actually used one of these? How do they work when the paper is muddy and wet? Im guessing not well? I only wonder because my wife has one lying around, got it from work, and I was amazed with it writing upside down.
I think I was more amazed that NASA spent $1 billion developing the pen to write upside down, when they could have simply used a pencil ;)