How do you get a core sample from a comet? There's so little gravity that if you used a scoop or a drill, you'd push yourself right off the surface. To solve this problem, we came up with a harpoon that collects samples. The concept is that the spacecraft flies next to the moving comet and fires from about 30 feet away, we would use a dampening system and propulsion to counteract the recoil. Our prototype harpoon is stainless steel, about one foot long, two inches wide and four pounds. We don't want it to be too lightweight, because it needs momentum to cut through the comet's surface. The harpoon hits the comet with its tip open, the material fills an internal cartridge, and a garage-door-like mechanism shuts behind it.