Filing velocity is intent, and the direction of that velocity tells you what a company thinks is worth owning. Looking across spacecraft-propulsion grants issued in 2020, the clearest pattern is a division of labor in what gets patented.
On the operations-and-integration side sit the primes. Boeing's US10689132B2 (June 2020) claims methods for performing propulsion operations with electric systems — the orchestration of power and thrust over a months-long orbit-raising campaign. Snecma's US10532833B2 (January 2020) claims a module integrating electric and solid propulsion. These are architecture and software plays: the physics of the thruster is assumed; the value is in flying it.
On the hardware side sit specialists and academics, often via the F03H classification for electric-propulsion plasma engines and the B64G 1/405 electric-propulsion-arrangement code. Microwave electrothermal thrusters, ion engines, and novel grid and cathode designs cluster here, filed by smaller entities and universities chasing the next efficiency increment.
The CPC distribution confirms the split. The prime filings lean on B64G 1/242 (attitude control), B64G 1/26 (jet motors), and a wide spread of power-management codes — the marks of a systems claim. The specialist filings concentrate in F03H 1/00xx, the marks of a device claim.
The strategic read for competitive-intel teams: in 2020, the established satellite builders had largely conceded that they would not out-innovate the thruster makers on raw physics, and were instead fencing in how electric propulsion is operated and integrated into a commercial bus. That is a mature-market posture — defending the operational moat rather than the component — and it tells you where the primes believed their durable advantage lived.