3/15/2023 - Written By Caleb Henry
The Space Development Agency is weeks away from launching the first satellites in its advanced LEO constellation, the Proliferated Warfighter Space Architecture (PWSA), but has not prepared user terminals to make use of the constellation. Speaking at Satellite 2023, SDA Technical Director Frank Turner said the agency is looking for electronically steered antennas that can link to the PWSA constellation, even going so far as to modestly fund technology development, an unusual step for a procurement agency. “Frankly we were very late to starting to look at the ground systems,” Turner said. PWSA is envisioned as a constellation of hundreds, potentially 1,000 satellites, more than half of which form the “transport layer” of communications satellites. Other layers bring different capabilities, most notably detection and tracking for missiles and hypersonic weapons. The transport layer will carry three different communications payloads, each with different ground segment needs:
- Link-16 radios: This is an encrypted, tactical communications system that normally only works through localized line-of-site networks. PWSA will expand Link-16 to space for current and future comms gear
- Ka-band: A common communications frequency for commercial and military satcom. This is where SDA will need electronically steered antennas
- Lasercomm: The PWSA constellation’s optical beams are mainly for crosslinks to create a high-speed relay network, but will also include some beams pointed to users on Earth
- Turner said SDA hired a point person for user terminals nine months ago. In contrast, the first PWSA satellites were ordered 31 months ago
- DoD has a long and beleaguered history of neglecting the ground segment, a move that results in launching satellites that then can’t be used much and fall short of their potential. The poster child for incomplete networks is the Navy’s Mobile User Objective System, a four-GEO-satellite network which was completed in 2016, but remains heavily underutilized, putting strain on legacy systems
- SDA will need to keep playing catch up to ensure user terminals are ready for PWSA once the constellation is operational. Perhaps the agency will benefit from companies that invested in terminals for other LEO Ka-band networks like Telesat Lightspeed and Amazon Kuiper?