When closed, Bullet Space Pens are the perfect size to carry in your wallet, pocket, purse, car glove box, organizer, or toolbox. When open, it's a full sized, evenly balanced writing instrument. he original Bullet Space Pen was conceived in July of 1948. The original Bullet Space Pen was conceived in July of 1948. Paul Fisher was soon machining a new 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 matte black finish with Space Shuttle Emblem.