A recent launch of low Earth orbit satellites enlarges the Proliferated Warfighter Space Architecture constellation, providing additional satellite communications to US forces worldwide.
The United States Department of Defence (US DOD) launched the Proliferated Warfighter Space Architecture (PWSA) in 2023 following a rebrand of the erstwhile National Defence Space Architecture (NDSA) initiative. The NDSA was a Space Development Agency (SDA) programme tasked with developing large numbers of small satellites performing various tasks deployed mostly in Low Earth Orbit (LEO), according to this report. LEO satellites typically orbit at altitudes of between 86 nautical miles/nm (160 kilometres/km) and 1,080nm (2,000km) above Earth.
In its own words the SDA, which forms a constituent part of the DOD, is tasked with “designing and rapidly deploying” the PWSA. The agency defines the PWSA a “a threat-driven constellation of small satellites that deliver critical services … from space”. These services “include low-latency data transport integrated with tactical data links, tracking of advanced missile threats, custody of time-critical land and maritime targets, and space-based battle management, to name a few”. The NDSA was redesignated as the PWSA in 2023 with reports stating that the agency felt the original moniker was too broad to encompass the specific tasks and missions the architecture’s constituent constellations will perform.
Tranches
PWSA capabilities are being delivered in a series of tranches. The first Tranche-1 satellites were launched on 10th September 2025 from Vandenburg airbase, California. A statement by the US Space Force (USSF) which owns the PWSA said that an initial 21 York Space Systems Tranche-1 data transport satellites were placed in LEO. The September 2025 launch was followed by a second in June 2026 which also took place at Vandenburg airbase and placed another 21 spacecraft in orbit.
Tranche-1 satellites form part of the PWSA’s transport layer providing Ka-band (26.5 gigahertz/GHz to 40GHz uplink/18GHz to 20GHz downlink) and Link-16 tactical data link (960 megahertz/MHz to 1.215GHz) connectivity. The latter is carried across L-band (1.2GHz to 1.8GHz/1.67GHz to 1.71GHz) radios furnishing the satellites. According to the SDA, Tranche-1 spacecraft will also demonstrate Ultra-High Frequency (UHF: 399MHz to 470MHz) and S-band (two gigahertz to 2.69GHz) connectivity.
An eventual 154 transport layer satellites are planned. The PWSA tracking layer, which will detect, identify and track ballistic missile launches, will comprise 28 spacecraft equipped with infrared seekers. The Tranche-1 constellation is operated from Grand Forks airbase, North Dakota and Redstone Arsenal, Alabama. The USSF can also call upon a global network of teleports to provide uplinks and downlinks to and from the spacecraft.
On 15th July, the SDA announced that the third launch of Tranche-1 satellites had occurred at Vandenburg airbase taking the total number of Tranche-1 spacecraft in the heavens to 63. As previously this latest launch comprised 21 York Space Systems transport layer satellites. A Space Development Agency announcement said the spacecraft will undergo testing before being raised to their circa 540nm (1,000km) orbital altitude. This latest group of satellites is expected to be declared operational in 2027.
A statement supplied to Armada by the SDA remarked that the satellites launched in July will provide Link-16 and Ka-band connectivity. Tranche-1 satellites are deployed in near-polar orbits providing “global coverage” including “persistent regional tactical datalinks, enhanced missile tracking (and) warning and beyond line-of-sight targeting capability”.
Compatibility
Tranche-1 users will not necessarily need to change or modify their satellite communications terminals to enjoy connectivity: “Many of the capabilities we are providing are backward compatible … For example, Tranche-1 will transmit Link-16 tactical data directly (from the satellites) to existing, unmodified user terminals already deployed in the field” says the SDA.
Although over 60 Tranche-1 spacecraft have been launched, it will be some time until the full complement of 154 satellites is in orbit which is expected to occur in 2027. Nonetheless, work is already ongoing concerning Tranche-2 which, according to the SDA statement, “is in the build phase”. This new constellation “will enable a broader user base by providing global persistence for all T1 capabilities, adds advanced tactical data link, preliminary missile defence and future proliferated missions”. Deployments of Tranche-2 spacecraft are expected to commence towards the end of the Tranche-1 launch campaign, the SDA statement concluded.
by Dr. Thomas Withington
