Lead isn't very useful for spaceflight. It's heavy, doesn't block radiation well, and doesn't have very many practical uses. Better would be organic compounds

Lead isn't very useful for spaceflight. It's heavy, doesn't block radiation well, and doesn't have very many practical uses. Better would be organic compounds (food, fecal waste), or water. One suggestion is to just line a ship with bags of water and then refill them with water recycled from urine and sweat. https://www.newscientist.com/article/dn23230-mars-trip-to-use-astronaut-poo-as-radiation-shield/ https://www.newscientist.com/article/dn23230-mars-trip-to-us... As the article mentions, none of that is good enough to protect you from a solar flare, so for that, you can potentially reorient the ship to have its aft end pointed to the sun to block as much radiation as possible.