Companies’ Perspective on New Data Links and Waveforms Sought for SDA Tranche 3 Transport Layer

The U.S. Space Force Space Development Agency’s (SDA) Tranche 2 Transport Layer-Gamma satellites are to include Ultra High Frequency (UHF) S-band connections, an advanced tactical data link, and enhanced, anti-jam waveforms. But Tranche 2 does not appear to be the end of the SDA innovation trail. The agency is seeking industry ideas on new data links and waveforms for Tranche 3.

A Nov. 6 SDA request for information (RFI) “seeks to inform SDA’s roadmap of future datalinks and/or waveforms and to guide the integration of these capabilities into future Tranches.”

“This RFI seeks to align datalink and waveform capabilities for baselining and/or demonstration in Tranche 3 with launches planned to begin in FY 2028,” the business notice said.

Industry ideas on optical communications waveforms for PWSA Tranche 3 and above “would include risk reduction efforts to support low data rate links, and long-range links, specifically space-to-space geometries of low earth orbit (LEO) to medium earth orbit (MEO) (L2M) and low earth orbit (LEO) to geosynchronous earth orbit (GEO) (L2G) ranges,” SDA said. “Responses to this RFI will specifically inform SDA’s Transport Layer Tranche 3 planning beginning in fiscal year 2024 (FY 2024) for subsequent acquisition efforts to slated to begin in FY 2025.”

SDA satellites are to have optical communications terminals (OCTs) to link with other satellites and ground terminals.

“While SDA has completed its internal review of potential additions to the Tranche 3 OCT standard, it is likely other military services, commands or other government agencies have completed architecture studies that have included industry or industry has internally studied or invested in this area,” the Nov. 6 RFI said. “Hence, SDA would like to leverage what has already been accomplished in cooperation with industry before making a final determination of optical standards that affect the Tranche 3 architecture. As currently envisioned, the Tranche 3 Transport Layer may have different space vehicle variants. Tranche 3 is expected to operate via multiple planes at approximately 1000km in 80–90-degree inclination orbits.”

On Oct. 30, SDA said that it had awarded Northrop Grumman a $732 million firm-fixed-price Other Transaction Authorities (OTA) contract to build 38 satellites for the Tranche 2 Transport Layer (T2TL)-Alpha constellation (Defense Daily, Oct. 30).

The 100 Tranche 2 Transport Layer-Alpha satellites are to transmit beyond line-of-sight Link 16 data to military forces from space, while the Tranche 2 Transport Layer-Beta satellites are to transmit over UHF S-band for tactical satellite communications, and the future Tranche 2 Transport Layer-Gamma satellites are to use an advanced tactical data link.

On Oct. 10, SDA awarded the first Alpha contract of $617 million to Denver’s York Space Systems for 62 satellites in eight orbital planes (Defense Daily, Oct. 23).

The satellites are part of SDA’s low Earth orbit-focused PWSA. The Transport Layer is to be the linchpin of DoD’s future Joint All Domain Command and Control infrastructure, which is to feature minimal lag time communications, sensor-to-shooter connectivity, and tactical satellite communication directly to platforms engaged in military operations.

In August, SDA awarded Lockheed Martin‘s Space division in Littleton, Colo., $818 million and Northrop Grumman’s Space Systems segment in Redondo Beach, Calif., $733 million–a total of more than $1.5 billion –for 72 Tranche 2 Transport Layer – Beta satellites–36 by each company (Defense Daily, Aug. 21). Lockheed Martin is to build those satellites at the company’s recently opened small satellite plant in Littleton.

While SDA had planned on 44 Gamma birds, SDA Director Derek Tournear told Silicon Valley Space Week’s Milsat Symposium on Oct. 19 that the requirement is now 24 Gamma satellites, as SDA is in discussions with a third, possible Tranche 2 Transport Layer-Beta vendor to put the advanced tactical data link on 24 additional Beta satellites.

SDA said that it expects to issue the Gamma solicitation by the end of this year. Tranche 2 is to have about 270 Transport and Tracking Layer satellites. The SDA Transport Layer satellites are to provide rapid sensor to shooter data, while the Tracking Layer satellites are to provide a significant leap in the detection and tracking of hypersonic and ballistic missiles.

This story initially appeared in affiliate publication Defense Daily.


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