The U.S. Defense Advanced Research Project Agency is seeking bids to provide four small satellites to demonstrate its fractionated spacecraft architecture in orbit.

The System F6 program is developing technology to enable the functions of a large, expensive monolithic satellite to be distributed across a cluster of smaller, less costly satellites wirelessly sharing resources such as computing and communications.

Darpa plans a six-month on-orbit demonstration in the second half of 2015, launching four small satellites into low Earth orbit as secondary payloads on Atlas V or Delta IV Evolved Expendable Launch Vehicles.

Each satellite will host an F6 Technical Package that will enable the wireless links between the spacecraft and allow semi-autonomous cluster-flight operations.

The cluster will demonstrate the ability to scatter, each spacecraft leaving a 20-km threat box within 5 min. of the command, and subsequently regathering.

Each of the four spacecraft will host a unique shared-resource payload . One will carry a SwiftBroadband transceiver that will communicate with an Inmarsat I-4 satellite in geostationary orbit to provide broadband connectivity from the cluster to the ground.

Other spacecraft in the cluster will carry a government-furnished sensor, high-performance computing element and a high-speed space-to-ground downlink transmitter.