The Department of Defense is currently in an active debate to determine the future of the U.S. Space Force's satellite data transport architecture. Officials are weighing two primary options for a next-generation, low-Earth orbit communications network and aim to finalize a path forward in time for the fiscal year 2027 budget proposal.
The decision centers on two developing constellations: the Space Development Agency's Transport Layer and a separate system known as MILNET, which is being developed by the National Reconnaissance Office. The outcome will shape how the U.S. military communicates and shares data across the globe for years to come.
Key Takeaways
- The Defense Department is deciding between two satellite constellations, the SDA's Transport Layer and the NRO's MILNET, for its future data network.
- A final decision is anticipated in time for the fiscal year 2027 budget cycle, which will be released in 2026.
- Funding for the next phase of the SDA's Transport Layer, known as Tranche 3, was paused in the 2026 budget request, indicating a strategic review.
- The ultimate goal is to create a resilient, high-bandwidth "internet in space" for military operations.
Two Competing Visions for Space Communications
The U.S. Space Force is at a strategic crossroads as it plans its next-generation satellite communications network. The service is evaluating at least two distinct systems, each designed with different primary functions but both intended to operate as a large constellation in low-Earth orbit.
One option is the Transport Layer, a core component of the Space Development Agency's (SDA) Proliferated Warfighter Space Architecture. This system is designed to provide secure, low-latency tactical communications, acting as the connective backbone for military sensors and personnel worldwide.
The other system under consideration is MILNET, a constellation developed by the National Reconnaissance Office (NRO) in collaboration with the Space Force. While less publicized, MILNET is engineered to handle the transmission of very large volumes of data, catering to different mission requirements than the SDA's network.
What is a Proliferated LEO Constellation?
Unlike traditional military satellites that are large, expensive, and located in high orbits, a proliferated low-Earth orbit (LEO) constellation consists of hundreds or thousands of smaller, more affordable satellites. This approach increases resilience—if one satellite fails or is disabled, the network can continue to function. It also reduces the time it takes for data to travel, known as latency.
A Pause for Strategic Reassessment
The debate gained prominence following the Space Force's fiscal year 2026 budget request. In that proposal, the service zeroed out funding for Tranche 3 of the SDA's Transport Layer, effectively pausing plans to solicit bids for the next batch of satellites.
This move signaled that senior leadership is taking a deliberate pause to evaluate how, or if, both the SDA and MILNET constellations fit into a single, cohesive architecture for the future. Both programs are in their initial stages of deployment, with plans to launch hundreds of satellites.
Defining the Military's 'Internet in Space'
According to Maj. Gen. Stephen Purdy, the Space Force’s acting acquisition executive, the service has a clear aspirational goal. Speaking at the Air & Space Forces Conference, he explained the military needs a robust, integrated network in space that functions like the internet.
"Preserving all of that activity and continuing to build out connectivity is where we’re headed," Purdy stated. "TBD on exactly how that’s going to form out."
Purdy highlighted that different military partners have competing priorities for such a network. Some require the ability to move massive data files, a capability central to MILNET's design. Others are more focused on the kind of tactical and secure communications that the SDA's Transport Layer is built to provide.
The current challenge for the Space Force is to devise a strategy that can satisfy both of these critical needs without creating redundant or incompatible systems.
SDA Progress to Date
The Space Development Agency has been moving forward with its architecture. In 2023, it launched a set of demonstration satellites to test the technology. Earlier in September 2025, the agency successfully launched its first batch of operational spacecraft, marking a significant step toward fielding its network.
The Role of Competition and Industry
A central theme in the ongoing discussions is the commitment to fostering competition and utilizing a diverse industrial base. While SpaceX is reported to be the contractor for the initial MILNET system, officials have clarified that the long-term plan involves multiple companies providing both satellites and ground equipment.
This approach aligns with the SDA's model, which relies on continuous competition to source satellites from various manufacturers. Maj. Gen. Purdy emphasized that this multi-provider strategy is essential, even if it introduces complexity.
Questions for the Future
As the Space Force debates the path forward, several key questions remain. Purdy noted that the service is focused on how MILNET could evolve and what new capabilities might be required.
"What we’re talking about is, what’s the future? Do you expand on that in the exact same format? Do you expand on that with different systems? How do you build a competitive aspect to that?" he said. "These are all debate topics."
He affirmed that maintaining and expanding connectivity is the priority. However, the technical and contractual methods for achieving this are precisely what is under review.
"We really have to do it because we want to take advantage of the industrial capability and the defense industrial base," Purdy explained. "The administration is kind of demanding it anyway, so we’re all aligned on that front. It’s just technically figuring out how to do it and then structurally within the program office."
The decision made in the coming months will set the course for the U.S. military's space-based communications infrastructure, impacting national security operations for decades.
