Most satellites die with fuel-empty tanks and perfectly good payloads. The fix is to send up a servicer that grabs the dying bird and does its station-keeping for it. US10850869B2, granted to Northrop Grumman Innovation Systems on December 1, 2020, claims the "spacecraft servicing devices and related assemblies, systems, and methods" that make that possible.
The CPC anchors it firmly in on-orbit operations: B64G 1/1078 (in-orbit servicing or assembly), plus B64G 1/40 and B64G 1/402 (propulsion plant arrangements) and B64G 1/646 (docking arrangements). The combination — docking plus propulsion plus servicing structure — is the whole concept of a life-extension vehicle distilled into classification codes.
The mechanism that matters is capture and mechanical mating to a client that was never designed to be serviced. Most GEO satellites have no docking port; the servicer has to grab a feature that exists for another reason — typically the apogee-engine nozzle or the launch-adapter ring. The claimed devices address exactly that: how to securely connect to an uncooperative client and then provide propulsion on its behalf.
This patent does not sit alone. Northrop has filed a long, deliberate family around servicing — later grants such as US10994867B2 and US11124318B2 carry the same title forward — which is itself the signal. Filing velocity is intent, and a multi-year continuation chain on one capability is how a prime fences in a new line of business.
A claims caveat: the value here is in the specific capture-and-service apparatus, not in the abstract idea of satellite servicing, which others (Astroscale, Maxar) also pursue. But because Northrop actually flew Mission Extension Vehicles to commercial GEO clients, this is one of the rare cases where the patent record and a demonstrated, revenue-generating capability line up.