Ok, only did a few minutes research but intuitively it doesn't make sense to me that ballpoint pens a) work in space but b) don't work upside down. There wouldn

Ok, only did a few minutes research but intuitively it doesn't make sense to me that ballpoint pens a) work in space but b) don't work upside down. There wouldn't be an upside down in space because of 0 gravity. Unless the author means upside down on earth?