Jacob Vlotman is a former propulsion scientist and costumed criminal active during the 1940s and 1950s formerly known as Spaceman as well as Mad Scientist.
Jacob Vlotman was born in Belgium. During his early adult years, he worked as a propulsion scientist. At some point, he immigrated to the United States and became a costumed villain. He dubbed Spaceman and later Mad Scientist by the media.
Spaceman encountered the Minutemen during the 1940s. During his reign, he also affiliated with costumed villain known as the Axis of Evil.
In 1959, he enacted a scheme of taking over New York City's water supply for reasons unknown. He was caught by Nite Owl, and after a daring chase across the city, he was cornered at an abandoned warehouse and was defeated by him. Vlotman was eventually arrested by the police and presumably incarcerated.
- During Hollis Mason's assault and murder by the Knot Tops, Mason fantasizes of beating Spaceman.