In reality, the space pen was independently developed by Paul C. Fisher, founder of the Fisher Pen Company, with $1 million of his own funds.[1][2][3][4] NASA tested and approved the pen for space use, especially since they were less flammable than pencils,[5] then purchased 400 pens at $6 per pen.[6] The Soviet Union subsequently also purchased the space pen for its Soyuz spaceflights.