Billions of dollars have been wasted, and needed capability lost, through launch failures and spacecraft malfunctions, but the US military seems unable to shed its desire for, and dependence on, large satellites that always cost more and take longer to build than expected. With its iconoclast's hat on, DARPA wants to obsolete the large "monolithic" satellite and replace it with a cluster of "fractionated" spacecraft modules launched seperately to rendezvous in orbit and link up wirelessly to perform the same mission.
The research agency has announced it plans to award Orbital Sciences a sole-source contract for Phase 2 of its System F6 program to demonstrate a satellite architecture based on fractionated modules. Phase 2 will include detail design of the spacecraft modules and ground station, a hardware-in-the-loop ground demonstration, a developer's kit for third-party design of fractionated modules, and a plan to flight test the concept.
Under DARPA's plan, all the functions performed by a large satellite would be divided between several smaller modules flying in loose formation, each responsible for a unique capability: computation, communications, navigation, sensing, etc. Individual elements of the cluster could be replaced if a launch fails, a module malfunctions or to allow the spacecraft to be upgraded once in orbit.
There are clearly huge technical challenges in getting mutliple free-flying spacecraft to rendevous, formate, wirelessly connect and function like a single satellite, but the biggest hurdle has to be cultural. Despite all its talk of operationally responsive space, the Pentagon seems unable to to turn its back on "exquisite" multi-billion-dollar satellites that take years to to define and develop and months to launch and check out.