The Fisher Space Pen is a ballpoint pen which works with
thixotropic ink and a pressurized ink cartridge. It can write on almost any substance ranging from butter to steel. It also can survive a wide array of temperatures, ranging from -50 to 160 degrees Fahrenheit. Fisher submitted his invention to
NASA. After vigorous testing, NASA approved Fisher's Space Pen. They purchased four hundred units at a reported price of $6.00 per unit (equivalent to approx. $60 in 2024). NASA purchased three different models: the 204, 207 and 208. The 204 had blue ink and a retraction button on the end. It was used on
Skylab and the
Apollo missions. It was later replaced by the 207. The 207 model was similar to the 204, except the retraction button had been moved to the side. The 208 model was the same as the 207, except it wrote in black ink. NASA modified these pens for use in the space program.
Velcro patches were added along with a standard metal clip to facilitate the storage and attachment of the pen. ==Political activities==