Paul Fisher had been manufacturing better writing instruments with a devotion to accuracy, intellectual honesty and fairness long before the United States Space Program began. But when astronauts started to explore the reaches of outer space, Fisher realized that no existing pen could perform in its boiling hot vacuum. His common sense approach and practical experiments resulted in the invention of the sealed-pressurized Fisher Space Pen. After months of rigorous testing, NASA selected the Fisher Space Pen for use on all of the Apollo missions. They are still used on all manned space flights both American and Russian.