What was Lonnie Johnson attempting to develop scientifically when the idea for the Super Soaker first struck him?

Answer

A heat pump utilizing pressurized water vapor

Johnson, a nuclear engineer at JPL, was working on the Galileo mission when he attempted to devise a heat pump that would use pressurized water vapor instead of environmentally unfriendly freon, leading to the accidental discovery.

What was Lonnie Johnson attempting to develop scientifically when the idea for the Super Soaker first struck him?
inventortoySuper SoakerLonnie Johnson