In a separate breach of contract suit filed in U.S. District Court in Atlanta in February, Johnson accuses Hasbro of violating a 1996 agreement to pay him Super Soaker royalties of 2 percent for “three-dimensional products” based on the appearance of the toy and 1 percent for “two-dimensional visual representations.”

The suit says Hasbro sold water guns that were “visually similar and based upon the appearance of Super Soaker water guns that incorporate Johnson’s technology.” Johnson also wanted the court to force Hasbro to open its books to determine sales of Super Soaker products from 2006 to 20012.

Johnson, a nuclear engineer, Tuskegee University Ph.D. and former NASA scientist, founded his company in 1989. It was the same year he first licensed the Super Soaker, which generated more than $200 million in retail sales two years later, the company said. The toy was licensed to Larami Corp., which was later purchased by Hasbro.

Johnson holds more than 80 patents, with more than 20 pending, the company said, which said sales of the Super Soaker have approached nearly $1 billion.

As an Alabama high school senior, Johnson finished building a remote-controlled robot with a reel-to-reel tape player for a brain and jukebox solenoids controlling its pneumatic limbs, according to a 2008 profile in the Atlanta Journal Constitution.

After graduating from Tuskegee he joined the Air Force, worked at the Air Force Weapons Laboratory at Sandia, worked for NASA’s Jet Propulsion Lab on the Galileo mission to Jupiter and the Mars Observer project, among others. He also helped design the Cassini robot probe that flew 740 million miles to Saturn.

He moved to Atlanta in 1990 before his Super Soaker invention made him wealthy. His inventions have included rechargeable battery technology and thermodynamic energy conversion technology.