Mobile User Objective System

The Mobile User Objective System (MUOS) is a Department of Defense (DoD) program managed by the U.S. Space Force, with procurement funding requested under budget line item MUOS00. The primary goal of MUOS is to provide secure, worldwide, beyond line-of-sight ultra-high frequency (UHF) narrowband satellite communications (SATCOM) for a diverse population of mobile and fixed-site terminal users across multiple services.

MUOS is designed to replace the aging UHF Follow-On (UFO) system, which has exceeded its intended operational life. The system is intended to significantly increase performance and capacity in support of critical Combatant Command SATCOM priorities.

The MUOS architecture consists of three main segments: Space, Ground, and User Entry. The Space Segment comprises five geosynchronous satellites, supporting a four-satellite operational constellation, and features both legacy UHF payloads (backward compatible with UFO) and Wideband Code Division Multiple Access (WCDMA) payloads that deliver cellular-like communications capabilities.

The User Entry Segment involves the integration of the MUOS waveform into user terminals, enabling enhanced connectivity and interoperability for deployed forces.

The Ground Segment is a key focus of current and future-year funding. It includes four Radio Access Facilities (RAFs) located in Wahiawa (Hawaii), Northwest Chesapeake (Virginia), Niscemi (Italy), and Geraldton (Australia), as well as two Satellite Control Facilities at Port Hueneme (California) and Schriever Space Force Base (Colorado). Each RAF is equipped with three large antennas and extensive hardware and software infrastructure. The ground sites collectively house thousands of major hardware components and hundreds of software applications.

Objectives for the ground segment center on upgrading hardware and software to address cybersecurity vulnerabilities, lifecycle management, and operational deficiencies. For FY 2026, MUOS funding will be used to procure and install Ground System updates at each of the six ground sites. These updates are necessary to correct hardware and software defects, replace obsolete components, and enhance system resiliency against emerging cybersecurity threats and denial-of-service attacks.

The upgrades are delivered as modification kits, which vary in scope depending on the complexity of the ground site infrastructure and the severity of the issues being addressed. The program also includes engineering, integration, testing, and delivery efforts to ensure that updates do not disrupt ongoing operations and that readiness levels meet warfighter requirements.

Specific objectives for each ground site are detailed in the budget justification. The Wahiawa Ground Site receives the largest share of modification funding due to its extensive hardware and software footprint, accounting for a significant portion of the total ground segment infrastructure. The Northwest Chesapeake site receives a smaller share, while Niscemi and Geraldton each account for a portion of the infrastructure. The two Satellite Control Facilities at Port Hueneme and Schriever SFB each represent a small percentage of the infrastructure and receive proportionate funding for upgrades and installation.

The Mawar Typhoon Disaster Relief Supplemental is a related budget line included in the FY 2025 appropriations, providing additional funding to address disaster-related impacts on MUOS infrastructure. This supplemental funding ensures continuity of operations and rapid recovery in the event of natural disasters affecting ground sites, particularly in the Indo-Pacific region.

The MUOS program's procurement objectives are aimed at sustaining and modernizing the ground segment to maintain secure, resilient, and high-capacity SATCOM for DoD users. The program leverages commercial, government, and international partnerships to respond to evolving adversarial threats and ensure operational agility. Planned upgrades and modifications are essential for maintaining system effectiveness, addressing obsolescence, and supporting the warfighter's communications needs in contested and dynamic operational environments.