You've covered the FFRDCs well, but another potential avenue of interest are the University Affiliated Research Centers (UARCs) -- APL is actually one of these

You've covered the FFRDCs well, but another potential avenue of interest are the University Affiliated Research Centers (UARCs) -- APL is actually one of these as opposed to an FFRDC. Another well-known UARC is GTRI. It is my understanding that UARCs are more flexible in how they can compete for contracts. FFRDCs are prevented from competing against private industry and the amount of work they have is directly controlled by congress through allocation of an annual ceiling of staff years of technical effort (STE) [0]. [0] https://www.gao.gov/assets/gao-22-105278.pdf https://www.gao.gov/assets/gao-22-105278.pdf