Most of what they do is Layer 2 and above, so it's hardware agnostic - prototyping on a Pi is fine.

Their work is gaining traction. DTN Bundle Protocol has been baselined for the LunaNet specification, which a bunch of private companies are designing to for lunar relay networks. Bundle Protocol is also currently on the CCSDS standards track so it should be formally part of the CCSDS protocol suite soon.

For those unaware: CCSDS is the Consultative Committee for Space Data Systems, they set widely used standards for spacecraft communications protocols. Basically anything beyond Earth orbit flies some variant of a CCSDS protocol stack, and a substantial chunk of missions in Earth orbit do as well, particularly if they are government funded. It's an international effort, China and Russia participate too so that everyone can communicate if need be.