Nasa patents a less expensive, but slower way, to send small probes to the move.

Nasa patents a less expensive, but slower way, to send small probes to the move.

Gravity assists (I.e. slingshots) are well known, but this one uses the Earth to get to the moon.  

https://www.businessinsider.com/nasa-patent-moon-travel-farside-lunar-orbit-dapper-dark-ages-2020-8

It is also interesting that Nasa used an inexpensive patent as a way to distribute this idea.