Defence contractor L3Harris Technologies announced it has successfully refurbished the primary mirror of the Space Surveillance Telescope (SST), a key sensor used by the United States Space Force to track satellites, debris and potential threats in deep orbit.
The work was completed in partnership with Australia, where the telescope is now based, and marks the first time the instrument’s primary mirror has undergone a full recoating since the facility began operating in the southern hemisphere.
Speaking at the Advanced Maui Optical and Space Surveillance Technologies Conference, Mission Delta 2 commander Barry Croker praised the achievement.
“Working with our partners in Western Australia, maintainers of the Space Surveillance Telescope have successfully completed their first primary mirror recoat, significantly improving our ability to detect small targets in geostationary orbit,” he said.
Situated in the southern hemisphere, the telescope provides wide-area monitoring of objects in geostationary orbit around 35,000 kilometres above Earth, where many of the world’s most important communications, navigation and intelligence satellites operate.
From operational spacecraft to fragments of space debris and emerging security threats, the telescope plays a central role in tracking objects in this vital orbital band.
The recent maintenance work involved removing, restoring and upgrading the telescope’s primary and tertiary mirrors, the precision optics that allow the system to detect and track objects at extreme distances.
Engineers repaired and reinforced key mounting points to improve the mirrors’ stability and performance in harsh operating conditions.
The primary mirror underwent a full refurbishment, including stripping the existing coating, deep cleaning and applying a new reflective layer using a specialised vacuum deposition system designed specifically for the telescope. The tertiary mirror was also cleaned to meet higher coating standards and received structural repairs to its support hardware.
Together, the upgrades restore and enhance the telescope’s optical performance, improving its ability to detect small and distant objects with greater accuracy.
The telescope was originally developed and operated at White Sands Missile Range in New Mexico before being relocated to Australia in 2017 as part of a growing US–Australia space surveillance partnership. It became fully operational in its new location in 2022.
Its southern location provides a unique vantage point for monitoring satellites and debris in geosynchronous orbit, complementing other sensors in the global space tracking network used by the United States and its allies.
According to L3Harris Space Systems president Jeff Hanke, maintaining the telescope’s performance is essential as space becomes more congested and strategically contested.
“SST is a cornerstone capability for protecting the nation’s space assets,” he said. “This milestone ensures Space Force operators continue to receive the precise, reliable sensor performance they need to detect threats, avoid collisions and defend the space infrastructure our military, economy and citizens depend on.”
Unlike satellites already in orbit, which cannot be serviced once they degrade, ground-based systems such as the Space Surveillance Telescope can be upgraded and restored over time.
That flexibility gives them an enduring advantage as governments increasingly rely on space infrastructure while also preparing for potential conflict in the domain.
With more than five decades of experience developing advanced electro-optical systems, L3Harris said its optics have flown on more than 200 space missions, supporting some of the most demanding surveillance and scientific applications.
The latest upgrade ensures the telescope will continue playing a vital role in monitoring Earth’s most important orbital corridors for years to come.