Under the Tranche 1 Demonstration and Experimentation System, or T1DES, program, Denver-based York will provide 12 satellites, as well as ground support systems, “to augment the Tranche 1 Transport Layer (T1TL) constellation with demonstration and experimentation of tactical satellite communication (TACSATCOM) and Integrated Broadcast Service (IBS) capabilities from low Earth orbit,” SDA said in a press release.

The T1TL satellites are SDA’s first set of mission-capable Transport Layer satellites. That program is part of SDA’s National Defense Space Architecture (NDSA) that eventually will comprise up to 500 satellites in LEO for six different mission types to augment and backup current Defense Department space capabilities. The birds are being developed to provide high-speed, high-volume data relay — a capability that will provide the backbone for future Joint All Domain Command and Control (JADC2).

The T1DES experiment is concentrating on using UHF- and SHF-band payloads for data transmission, rather than Link 16 and K-band communications being used by the T1TL satellites, explained SDA Director Derek Tournear in a press conference today.

“They will utilize different radios that that go down to special users in the field and special platforms, utilizing the UHF- and S-band frequencies,” he said. “[A] lot of those capabilities — especially for example, the Integrated Broadcast System or IBS — are typically handled by geosynchronous satellites today. So, because of that, there are actually a lot of technical challenges.”

SDA plans to launch the T1DES in 2025 on four launches procured through the Space Force’s National Security Space Launch Phase 2 contract, the press release said.

Tournear said that the plan is to transition the T1DES capabilities, if proven successful, into the next tranche of Transport Layer satellites. That decision will be made by the agency’s Warfighter Council when it next meets on March 23 to see the “baseline minimum viable product” for Tranche 2,” he said.

“If all is going well with the acquisition and development of T1DES, our intention would be to have at least a large fraction of the Tranche 2 Transport Layer be populated with the same capabilities that we’ll be demonstrating on on T1DES. So that’s, that is the plan,” he said.

SDA — which smoothly transferred from DoD’s Office of Research and Evaluation to the Space Force on Oct. 1 — only two days ago announced an award in a related experimental effort for building out the NDSA.

The NDSA Experimental Testbed, or NExT, program which will support both the Transport Layer’s data relay mission and the agency’s Tracking Layer of missile warning/tracking birds.

NExT “will demonstrate low-latency data transport and beyond line-of-sight command and control” using the T1TL satellites to connect “additional space vehicles with different mission payload configurations” that are not a part of the planned NSDA, according to an SDA press release.

The NExT satellites originally were conceived as part of the T1DES effort, but Tournear explained that the agency decided to break them out into a new initiative because they have foundational differences,

For example, he elaborated that NExT payloads were “all government provided,” with most coming from other government mission partners — primarily the Army. Further, he said, and the NExT birds are flying at a much lower orbit than the T1DES satellites, at around 550 kilometers “versus the T1DES satellites that will be at 1,000 kilometers.”

Most importantly, NExT will just be testing out high-risk experimental payloads to do a plethora of different missions” versus the low-risk nature of the T1DES payloads.

SDA awarded Ball Aerospace a Other Transaction prototype agreement, with a total potential value of approximately $176 million for “development, manufacture, deployment, launch, and operations of a set of 10 space vehicles and mission-enabling ground systems, set to fly beginning in 2024,” the release added.

“So, it is an exciting time at SDA,” said Tournear. “We hope that [with] the change into the Space Force that this transfer enhances our ability to deliver quickly, and as you see it hasn’t slowed us down from from getting these contracts awarded.”