According to news from the Breaking Defense website on June 23, 2021, the U.S. Space Development Agency (SDA) plans to launch five demonstrative payloads to test the realization or enhancement of the U.S. Department of Defense’s resilient satellite communications backbone for all-domain operations—optical communications, And test on-board (rather than ground) multi-sensor data fusion capabilities.
The five payloads, four carried by custom microsatellites and one aboard a commercial satellite, are part of three separate technical experiments. Two of the experiments focused on laser links, each involving two satellites: one experiment focused on the inter-satellite link; the other focused on the link from the satellite to the ground-based MQ-9 Reaper drone. The third test (with payload) was to test the onboard processor for command and control data.
SDA has invested less than $21 million in these three experiments via SpaceX’s Transporter 2 “rocket together” mission, and the valuable information gleaned from these experiments will lay the foundation for the U.S. defense space architecture. The SDA also highlighted that the Optical Inter-Satellite Link (OISL) is a key enabling capability at the transport layer, the Joint All-Domain Command and Control (JADC2) communications backbone. The JADC2 backbone will require orbital data fusion to rapidly process data from sensors and shooters in the air, land, sea, space and cyber domains before sending it to commanders.
The U.S. “Diffuse Low Orbit” defense space architecture consists of seven “layers,” including six different constellations of hundreds of satellites — many planned to operate in 800- to 1,000-kilometer orbits — and a ground operational layer . Each satellite will weigh a few hundred kilograms and cost around $10 million.
The transport layer is probably the most critical part of the SDA planning constellation, but SDA also focuses on missile warning and tracking. SDA’s “tracking layer” will use LEO satellites to complement and serve as a critical backup to the Department of Defense’s small number of extremely expensive Space-Based Infrared System (SBIRS) and subsequent Next-Gen Overhead Persistent Infrared System (Next-Gen OPIR) satellites. SDA is also developing a wide-field infrared sensor to complement the US Missile Defense Agency’s new mid-field hypersonic and ballistic-tracking space-based sensors (HBTSS), which would allow better detection and tracking of ballistic missiles, but would also be ugly to a hypersonic cruise missile in flight.
SDA expects to launch “Phase 0” of the U.S. Defense Space Architecture in September 2022, when SDA will put the first 28 satellites into orbit (20 transport layer satellites, 8 tracking layer satellites). Since then, SDA will launch new satellites every two years.
The five payloads are part of SpaceX’s Transporter 2 “carpool” mission, according to senior SDA officials. The five payloads are:
Mandrake II: Two satellites, developed by DARPA and the U.S. Air Force Research Laboratory (AFRL), that demonstrate inter-satellite optical cross-links. The satellites are manufactured by Astro Digital and carry optical inter-satellite link payloads developed by SA Photonics. The two satellites are part of DARPA’s “Black Jack” program to demonstrate the military use of small, inexpensive satellites.
Laser Interconnection and Networking Communication System: Two optical inter-satellite link demonstration satellites developed by General Atomics; these satellites will be connected to the MQ-9 UAV, also manufactured by General Atomics.
“Prototype on Orbital Testbed (POET)”: SDA’s demonstration of a new foundational software that will enable operational management and oversight of the SDA constellation. POET will build on DARPA’s Black Jack’s Pit Boss battle management, command, control and communications (BMC3) work, as well as include the Sagittarius-A* Innoflight data fusion processor and software developed by Scientific Systems. The processor will be carried on the YAM-3 satellite operated by Loft Orbital in the United States.