Paul Fisher’s company was originally a maker of refill ball-point cartridges, established in the 1950s. Fisher leapt in to notoriety in the mid-1960s for developing an system that would work in extremes of temperature and pressure, using “ink” that was only liquid when agitated by the ball, and moved forward by a nitrogen-pressurized piston. Note that this development was done entirely on private funds, and offered to NASA only once it was functional, and not used until 1968; legends regarding vast expenses to develop something that matched the Russian pencil are no more than stories, and in fact the Fisher pen was also sold to the Soviet space program in 1969.
The company itself is going along nicely, although Paul Fisher himself is not; he died in 2006. His son has taken over the company, and they appear to be going along in the laudable family pen company style that was fairly common in the first half of the last century.
The sharp-eyed reader will notice that, apart from the technicality of containing its own reserve of ink, a pen made by Fisher is not a fountain pen. This is entirely true, and I include them in my round-up because of a softness in my head for the trappings of the great Space Race which was underway during my childhood, and because they do represent one of the few useful advances in writing instruments which ballpoints can claim.
Models I’ve examined: