SDA lays out plans for third batch of data transport, missile tracking satellites

The Space Development Agency is finalizing requirements and upcoming solicitations for around 200 satellites that will make up the third tranche of its Proliferated Warfighter Space Architecture (PWSA) constellation.

According to a recent notice to industry posted on Sam.gov, SDA intends to release the first draft solicitations for Tranche 3 of the PWSA’s tracking and transport layers in early 2025. Those satellites — slated to begin launching in 2028 — are expected to provide advancements in capabilities from previous tranches, as well as feature new warfighting applications.

An SDA spokesperson confirmed that approximately 200 satellites will make up Tranche 3 of the PWSA. The constellation is being developed and fielded in batches or “tranches,” and it’s expected to eventually comprise hundreds of space vehicles in low-Earth orbit that carry critical technologies for data transport and missile defense missions.

The Tranche 3 transport layer is being divided into three separate variants — Upsilon, Sigma and Lambda — that each have slightly different capabilities, the same strategy SDA used to develop transport satellites for Tranche 2’s transport layer. The agency expects to issue up to two awards for each variant, according to the notice.

A draft solicitation for the Upsilon variant is slated be published in early 2025, and those for the Sigma and Lambda variants are to be released in the spring and summer of 2025, respectively. The final solicitation for the Upsilon and Sigma variants are anticipated to be released during the third quarter of fiscal 2025, followed by the final Lambda solicitation in the fourth quarter of FY ’25.

Because solicitations are still being finalized, the agency could not provide details as to what specific capabilities will be in each variant. However, the notice stated that Tranche 3 transport satellites will support “the advancement of the PWSA’s Tracking capabilities by adding capacity and robustness to the global mesh network.” 

SDA will also build out the PWSA’s ability to conduct position, navigation and timing (PNT) in Tranche 3, according to the notice. While transport satellites in the first and second batches are expected to deliver initial PNT capabilities, the third tranche will feature enhancements in time transfer and ranging technologies, the SDA spokesperson told DefenseScoop.

As for the Tranche 3 tracking layer, the agency plans to release a draft solicitation in the spring of 2025 and the final version in the summer, according to the notice. SDA previously published a request for information in July that sought industry feedback on its plans for the third tracking layer, which will include systems that are equipped with infrared sensors and able to provide warfighters with fire control-quality data.

At the same time, the notice indicated that SDA is considering development of a PWSA Enterprise Ground effort, although it didn’t provide specific details or timelines for when solicitations might be published.

The notice to industry for Tranche 3 came after the agency decided to adjust its acquisition strategy for the PWSA to allow more time for vendors to build their platforms. In September, SDA Director Derek Tournear said previous contracts required industry to have systems ready to launch within two-and-a-half years of the contract date, but the agency has since extended that to three years.