A new report from the U.S. Government Accountability Office (GAO) cautions that the Space Development Agency’s (SDA) effort to build a constellation of missile warning and tracking satellites faces significant risks that could hinder the delivery of critical defense capabilities.

The report, titled, “Missile Warning Satellites: Space Development Agency Should Be More Realistic and Transparent About Risks to Capability Delivery," examines the department’s Proliferated Warfighter Space Architecture (PWSA), which is a multi-layer network of satellites intended to provide early warning and tracking of missile threats, including hypersonic and ballistic systems. 

The architecture is expected to include 300–500 satellites in low Earth orbit with collective costs projected at nearly $35 billion through fiscal year 2029.

“SDA is overestimating the technology readiness": GAO

Space News reported on January 28 of this year that the GAO found that SDA’s current planning may be overly optimistic, particularly regarding the readiness of technologies underlying its missile warning and tracking satellites. That outlet reported that “The Space Development Agency is at risk of being unable to deliver capability as quickly as planned,” citing optimistic assessments of technology readiness for both spacecraft and ground systems.

“SDA is overestimating the technology readiness of some critical elements it plans to use,” read the report, released on Wednesday. "This includes the spacecraft, which must be modified for the mission. As a result, contractors have performed additional unplanned work, which has added to already delayed schedules."

Officials interviewed by GAO who declined to be named said individual satellite contractors are still addressing these integration challenges, raising the risk that anticipated capabilities may not be available on the agency’s planned timelines.

The report also criticized SDA’s approach to reporting progress. While the agency has moved ahead on contracts for multiple satellite “tranches” — phases of development with planned launches every two years — the GAO noted that milestone announcements “do not reflect schedule risks.” It added that SDA “has not developed an overall or architecture-level schedule” that would show how delays in one tranche could affect the broader effort.

Another key finding focused on SDA’s requirements process. According to the GAO, some military combatant commands — the intended users of the missile warning data — reported limited visibility into how SDA defines requirements and when specific capabilities will be delivered.

“SDA is not sufficiently collaborating with combatant commands, which report having insufficient insight into how SDA defines requirements and when, or whether, SDA will deliver planned capabilities,” the report said. "Consequently, SDA is at risk of delivering satellites that do not meet warfighter needs."

The watchdog reported that the SDA "continued to award new tranche contracts every 2 years irrespective of satellite performance."

The GAO suggested the SDA make some changes 

"SDA relies on contractor schedules for each tranche but has not developed an overall or architecture-level schedule. Using an architecture-level schedule to monitor schedule risks would better position SDA and stakeholders to understand earlier how schedule changes affect SDA’s progress in delivering capabilities," the report said.

On the financial side, the watchdog found that the Department of Defense, which President Trump renamed The Department of War, “does not know the life-cycle cost to deliver missile warning and tracking capabilities” because a reliable estimate has not yet been established. The report said SDA required only limited cost data from contractors for early tranches, preventing a comprehensive long-term cost picture.

To address these concerns, GAO made six recommendations, urging the Department of the Air Force, which oversees SDA acquisitions, to assess the readiness of "new critical technologies," including:

• "Improve collaboration with warfighter stakeholders in defining requirements;" 
• Develop "architecture-level schedule and reliable, data-informed" cost estimates; 
• Include requirements for "cost data" in new contract awards; and
• Establish data-driven cost estimates and update them regularly.

According to the GAO report, the Department of Defense concurred with five of the recommendations and partially concurred with one.