Chrome Bullet Space Pen. When closed, the Bullet Space Pen is the perfect size to carry in your wallet, pocket, purse, car glove box, organizer or toolbox. When open its a full sized, evenly balanced writing instrument. The original Bullet Space Pen was conceived in July of 1948. Paul Fisher was soon machining a pen design shaped from solid aluminum. It became our first Fisher ball point pen, the #400 Bullet Pen, and arguably the most popular pen of the twentieth century. This pen is now all brass with a Chrome finish.