Northrop to Build Space Force's Resilient Radar System-Ground Constellation
The U.S. Space Force has given a name and a builder to its plan for tracking moving targets on the ground from orbit. The Ground Moving Target Indicator program is now the Resilient Radar System-Ground, or RRS-G, and Northrop Grumman is the prime contractor for the satellites. Both details were disclosed at the Air & Space Forces Association conference, closing a period in which officials had talked about placing ground-tracking sensors in orbit by 2028 without identifying the program or the company building it.
The constellation is a joint effort with the National Reconnaissance Office. Launches are expected to begin within the next two years, which keeps the program on the 2028 timeline the service has cited before. The Space Force established the 77th Surveillance Squadron in August 2026 to manage the missions.
What Resilient Radar System-Ground Is Built to Do
RRS-G uses radar payloads to find and follow moving ground and maritime targets in daylight or darkness and in any weather. That round-the-clock, all-weather coverage is the capability the Space Force has been missing since the crewed aircraft that once handled the mission left service.
Orbital sensing is designed to replace or augment legacy airborne surveillance platforms, among them the E-3 Sentry AWACS and the Northrop Grumman-built E-8 Joint STARS. The E-8 tracked ground vehicles and some aircraft, collected imagery and relayed tactical data, and it carried out battle management and command-and-control duties before the Air Force retired it.
Moving that work to satellites removes the need to keep aircraft and crews on station. It also extends coverage into areas where aircraft cannot loiter for long stretches.
The choice of radar matters for what the constellation can promise. Optical satellites cannot see through cloud cover or operate in darkness, so a radar payload is what makes around-the-clock tracking of vehicles and vessels feasible from orbit rather than dependent on clear skies.
The Gap Left by Retired Aircraft
The E-8 Joint STARS was a Northrop Grumman product, which means the company that built the aircraft is now building its orbital successor. That continuity matters for the industrial base, since the radar, mission-processing and ground-segment skills developed across decades of airborne ground surveillance carry over to a satellite constellation even though the platform changes.
The service stood up the 77th Surveillance Squadron before the first launch, a step that indicates it intends to run the constellation as a standing mission rather than a technology demonstration. Standing up a unit ahead of hardware means personnel, training pipelines and operational concepts are being built alongside the spacecraft.
The United States Space Force is a young service, established in December 2019, and RRS-G would rank among its first dedicated surveillance constellations. Military space activity inside the Department of Defense reaches back to the years after the Second World War, when General Henry H. Arnold identified space as an area of military importance.
Two Constellations, Two Target Sets
RRS-G is one half of a broader shift of surveillance from air to orbit. The Space Force is funding two constellations with different target sets and different prime contractors.
| Program | Target set | Prime | Status and funding |
|---|---|---|---|
| RRS-G (GMTI) | Ground and maritime moving targets | Northrop Grumman | Launches within two years; FY2027 request of $1.02B procurement and about $1.1B R&D |
| SB-AMTI | Airborne moving targets | SpaceX | Prototypes launch late September 2026; $4.16B award; operational constellation targeted for 2028 |
The split is deliberate. AMTI covers airborne targets, the mission AWACS aircraft once flew, while GMTI handles vehicles and vessels on the surface. SB-AMTI prototypes are scheduled to launch in late September 2026, giving the service early data on how orbital radar performs against airborne targets.
SpaceX holds a $4.16 billion award for the operational AMTI constellation, targeted for 2028, and more than $7 billion in reconciliation funds has been requested to support it. Northrop Grumman's RRS-G work runs on a separate funding line: the FY2027 budget request carries $1.02 billion for GMTI procurement and about $1.1 billion for related research and development.
The two missions also differ in engineering difficulty. Airborne targets move quickly against open sky, while ground targets have to be separated from terrain and clutter, which puts different demands on radar design and on the processing that runs below. The Resilient Radar System-Ground adds vessels to that list, widening the set of targets the constellation must resolve.
Competitively, the two awards anchor different primes in different mission lines. SpaceX, whose launch business already serves the Space Force, now holds the airborne tracking line, while Northrop Grumman holds ground and maritime tracking. Neither company has a public foothold in the other's target set, which leaves the service with two specialized suppliers rather than one integrator across both.
How the Work Is Divided
The NRO will own satellite command and control, sustainment and the ground architecture, while the Space Force is the lead military operator. That arrangement puts the intelligence community's satellite operators in charge of flying the spacecraft and the military service in charge of the operational chain that turns tracking data into decisions.
The NRO has been restructuring how it collects and processes signals intelligence for multi-domain fusion, and it is working with the Space Force to field space-based GMTI. Pairing an intelligence agency's spacecraft experience with a military operator's requirements is the model both organizations are using.
For Northrop Grumman, the award places the company inside two of the service's largest space surveillance efforts. Its space business already spans missile warning, satellite tracking, propulsion and launch systems, and the company employs roughly 95,000 people across defense, aeronautics, space and cyber work. RRS-G adds a ground-surveillance mission line backed by more than $1 billion in FY2027 procurement funding.
Northrop Grumman also builds ground-based radar, including the AN/TPS-80 Ground/Air Task-Oriented Radar supplied to U.S. and international forces. That radar heritage sits alongside its spacecraft work, giving the company both halves of the RRS-G mission: the sensor and the satellite that carries it into orbit.
What the Schedule and Budget Reveal
A launch window inside two years is fast for a constellation that had no public name or prime contractor until this week. Satellite manufacturing, integration and launch campaigns usually run longer from a standing start, so the timeline depends on how much work Northrop Grumman has already completed.
The FY2027 request is the clearest statement of intent. Roughly $2.1 billion for RRS-G procurement and research, set alongside a separate multi-billion-dollar AMTI line, shows the service funding two orbital surveillance architectures at once rather than choosing between them. Requests of that size make RRS-G one of the service's larger new space programs, and they commit money before a single satellite reaches orbit.
The numbers also set expectations for suppliers. A procurement line above $1 billion for a single constellation creates demand for radar payloads, spacecraft buses and ground-processing hardware, and it signals to subcontractors that the work extends beyond a first batch of satellites.
Running both programs in parallel carries tradeoffs. Budgets and engineering talent are finite, and splitting the work between two primes divides both. It also spreads risk, since weak performance against one class of target would not stall the other program.
Why this matters
RRS-G moves a mission that depended on crewed aircraft into a satellite constellation that can watch ground and maritime traffic through weather and darkness. Naming the program and awarding the prime contract turn a concept the Space Force has discussed for years into a funded effort with a squadron already standing up to operate it. The FY2027 request shows where the surveillance budget is heading: two parallel constellations, two primes and about $2.1 billion committed to ground tracking in a single fiscal year. Whether orbital radar can absorb a mission that crewed aircraft carried for decades now depends on whether the launch schedule holds.
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Researched and cross-referenced against primary sources by the Bytevyte editorial team. This article was generated with the assistance of artificial intelligence and reviewed by the Bytevyte editorial team.