- See Van Gelder for other articles with titles that contain, either by relationship or by coincidence, this character's surname.
Doctor Simon Van Gelder was a respected Human scientist who was assigned to the Tantalus Penal Colony as Dr. Tristan Adams associate in 2266. During Van Gelder's time working with Dr. Adams, the two developed and constructed an experimental device known as the neural neutralizer. The device was designed to be able to rehabilitate a criminal by conditioning their mental responses to stimuli.
However, Adams saw the device as a means to control other individuals and decided to remove the threat of Van Gelder by giving him prolonged exposure to the neutralizer. Fortunately, Van Gelder was able to escape from the colony after hiding himself in a cargo container that was transported aboard the USS Enterprise. However, he was discovered and transported back to the colony, and Dr. Adams convinced Captain James T. Kirk that Van Gelder had exposed himself to the device as a test. While the Enterprise crew initially accepted Adams explanation, Commander Spock and Dr. Leonard McCoy later grew suspicious and performed a mind meld on Van Gelder to learn the truth.
With the truth finally revealed, the Enterprise crew prevented Adams from gaining Captain Kirk under his control, and once Van Gelder was restored to full health, he had the neutralizer destroyed. (TOS episode: "Dagger of the Mind")
Van Gelder was still alive in the 2370s and was still living in the Tantalus colony on Tantalus V. He would send items to Adams at the Central Bureau of Rehabilitation in Stockholm via the Planet 10 Shipping company. These cargo items were often routed through Deep Space 9. (Star Trek: Deep Space Nine set decoration; ST reference: Star Trek Encyclopedia)