Did one single guy really "invent" gravity assist?

NASA Inspector General to Congress in regards to SLS: "Relying on such an expensive, single-use rocket system will, in our judgement, inhibit if not derail NASA's ability to sustain its long term human exploration goals to the Moon and Mars."

A new gravity sensor used atoms’ weird quantum behavior to peer underground

Quantum Gravity Sensor Breakthrough Paves Way for Groundbreaking Map of World Under Earth’s Surface