NASA is looking for someone to take over its most critical space communications network — and the window to do it safely is closing.
The space agency issued a draft solicitation April 10 for Project NEXUS, a program to replace the aging Tracking and Data Relay Satellite System, known as TDRSS, with commercially provided Ka-band relay services. If no replacement is operational before the existing constellation ages out, Hubble and the International Space Station lose their only communication link mid-mission. Those spacecraft cannot switch to alternative systems. There is no backup.
The 2029-2031 timeframe is the red line. As more TDRS satellites reach end of life, the gap between what exists and what must replace it has to close before something critical goes dark. NASA put the dates on the calendar and asked industry to fill it.
The broader pattern is the story. NASA has done this before: proved a capability worked, then handed it to commercial operators to scale. GPS went from military system to public utility in 1983. The Commercial Orbital Transportation Services program, launched in 2006, funded SpaceX and Orbital Sciences to build cargo vehicles for the International Space Station — later taking over missions the government had performed itself. Commercial imagery followed the same arc. NEXUS is the next iteration applied to data relay. The difference this time is backward compatibility: the requirement to communicate using 1980s Ka-band protocols may determine who can bid at all.
Kevin Coggins, NASA's deputy director of the Space Communications and Navigation program, said it plainly in the draft solicitation: "What we had for so long is reaching end of life and needs to evolve." He is correct, and the implication is uncomfortable — backward compatibility with existing systems is not a feature, it is a moat.
The TDRSS constellation has seven operational satellites, two in storage, three retired, and one lost in a launch failure. TDRS-1 launched April 5, 1983. The most recent, TDRS-M, launched August 18, 2017. The network was designed for a different era of space infrastructure and has been kept operational past its intended lifespan through storage orbit reassignments and careful fuel management. Seven of twelve is not a robust margin when the payloads are Hubble and the station.
Hubble and the ISS cannot shift to alternative communication systems and risk loss of telemetry, tracking, and command services if TDRSS fails, according to the draft solicitation. That is a single-point-of-failure acknowledgment from an agency that rarely states the obvious. The existing constellation is not being replaced on a schedule — it is being replaced before something fails.
The NEXUS structure is a three-phase competition with progressive downselects. Phase 1 matures concepts over six months. Phase 2 develops systems and runs ground tests over 15 months. Phase 3 runs a three-month orbital demonstration. NASA plans multiple initial firm-fixed-price awards, reducing the pool based on demonstrated performance, technical credibility, and commercial viability. Phase 1 begins September 2026 if the schedule holds.
The commercial viability requirement is intentional. NASA does not expect to be the sole customer. The solicitation explicitly asks for solutions supported by a broader business case beyond NASA — the relay service must work for non-NASA spacecraft operators or the economics do not work on a 15-year service contract. This is COTS logic applied to communications infrastructure: NASA funds development and provides the anchor tenant, commercial operators scale the service for the rest of the market.
The backward compatibility requirement is where the story gets complicated for would-be competitors. NEXUS requires solutions be backward compatible with legacy TDRS Ka-band services for a minimum of 15 years of operational service. That specification is not a technical detail — it determines who can bid. Companies that have worked with TDRSS directly have a structural advantage. New entrants attempting to build a modern relay service from scratch must also reverse-engineer 1980s protocol layers on top of current hardware. The requirement was written for the existing supply chain, not to invite competition.
The bid timeline is tight. Final solicitation is expected May 14, 2026, with proposals due June 5 and Phase 1 work beginning by September. NASA has run this playbook before. The question for commercial space communications is whether the backward compatibility requirement is a bridge to transition or a wall that keeps the same players in place.
For readers tracking the satcom market, NEXUS is a signal of how NASA will acquire space infrastructure going forward — commercial services with a government anchor tenant rather than government-owned systems. For anyone building or investing in spacecraft operations, the program is an early look at which companies are positioned to own a critical piece of orbital infrastructure for the next 15 years. The supply chain is not equally open to all entrants. The ones who already know TDRS are the ones who will be asked to replace it.
