The TDRS system, a longstanding backbone for communication links between Earth and satellites in low-Earth orbit, is set to pass the baton to wideband polylingual terminals. This novel technology offers a potential game-changer for future missions, delivering seamless roaming capabilities. By employing software defined radios (SDR), these terminals can receive communication signals from various SATCOM service providers. The SDR technology, developed over the last decade, uniquely enables in-orbit waveform change, facilitating the adoption of new and evolving commercial services.

At the heart of this transition is the Wideband User Terminal project, aimed at achieving interoperability between government and commercial networks for near-Earth services. Drawing parallels with cellphone technology, where roaming has long been a standard feature, wideband terminals are poised to bring similar flexibility to space communications. This different approach is a significant leap from past practices, enabling missions to switch networks without service interruption.

The groundbreaking development and testing of wideband interoperability technology were conducted at NASA's Glenn Research Center in Cleveland, Ohio. A notable milestone was achieved in 2021, with the first successful test of roaming between multiple network providers.

The integration of industry and government network providers is a key element in NASA's stride towards commercialization. While the TDRS system has served NASA for nearly four decades, its design did not originally account for network interoperability. The SCaN program is now developing wideband technology to ease this transition, offering a safeguard by maintaining connections to the reliable TDRS network while private industry continues to refine their space-based services.

The benefits of this interoperability are manifold, including reducing the risk of data loss and communication delays. Furthermore, providing missions with a selection of network providers can prevent vendor lock-in and ensure mission execution stays on track, even under unforeseen circumstances.

A pivotal initiative within this context is the collaboration between NASA's Wideband Terminal Project and Johns Hopkins University Applied Physics Laboratory to test the Polylingual Experimental Terminal (PExT). Set for integration with a York Space Systems S-class Bus and a launch aboard SpaceX Falcon 9 Transporter-11 in June 2024, PExT aims to demonstrate a myriad of capabilities. These include interoperability through contact and link management, forward and return link data flow, and roaming across both NASA's TDRS network and three commercial relay networks.

The PExT Wideband Terminal, boasting a wide frequency range covering both commercial and government Ka-Band allocations and scalable 0.6-meter antennas, is designed to handle initial data rates of up to 90 Mbps Forward and 375 Mbps Return. Future projections indicate capabilities reaching up to 490 Mbps Forward and 1 Gbps Return. Importantly, it supports both NASA and commercial waveforms, such as DVB-S2 and CCSDS TDRSS.

As the Wideband Project continues to invite the mission user community for extended operation experiments, the upcoming period is set to be a transformative one for space communication. With capabilities like self-pointing, intra-/inter-network link handoff, and link fault recovery, the PExT demonstration represents not just a technical achievement, but a significant step towards a new era of space communication where flexibility and resilience are paramount.

For more information about the Wideband Project and opportunities for involvement, interested parties are encouraged to reach out to Marie T. Piasecki, the Wideband Technology Lead at NASA. ( marie.t.piasecki at nasa.gov )

Related Links
Space Communications and Navigation (SCaN) Program
Space Technology News - Applications and Research