Behind the Scenes: How Moog Keeps Rubin’s “Cosmic Movie” in Focus

Imagine watching a ten-year time-lapse of the night sky, a movie that reveals exploding stars, wandering asteroids, and subtle ripples in space that tell us about the structure of the universe. That is the Vera C. Rubin Observatory’s mission. Perched on Cerro Pachon in Chile, the observatory’s giant mirrors and a 3.2 gigapixel camera capture a new snapshot of the cosmos every 40 seconds. Over the survey, Rubin will return to each patch of sky about 800 times, building the most detailed record of the changing night sky ever made.

Behind each sharp image is a set of quiet, precise helpers supplied by Moog. They do not draw attention, but they make the discoveries possible.

Think of the telescope as a giant camera with delicate parts that must stay perfectly aligned while the Earth turns beneath it. Moog provided two kinds of gear that do the fine work: hexapod platforms and a camera rotator.

Hexapods are like a coordinated set of ultra-precise robotic legs. Each one can nudge the secondary mirror or the camera in tiny steps, so the focus and alignment stay exact. The camera rotator is like a steady hand that keeps the image oriented correctly as the telescope tracks the sky.

These systems work together so each frame is crisp and ready for science. Tiny shifts in alignment can turn a clear image into a blur. Those tiny shifts can hide a newly appearing supernova or make a fast-moving object look smeared. The motions Moog’s systems make are often smaller than the width of a human hair, and they happen thousands of times every night.

Prior to delivery, Moog engineers rigorously tested and qualified the systems in controlled environments. These tests included alignment checks across temperature swings from -10 degrees Celsius to +20 degrees Celsius and vibration tests to validate robustness. Software routines that coordinate the hexapods and the rotator were developed and validated to ensure moves would be smooth and safe once installed.

After delivery, the Vera C. Rubin Observatory’s team completed the on-site integration, system tuning, and commissioning. This careful handoff ensured that the observatory could begin its nightly survey with confidence in the performance of these critical components.

For a project designed to run for a decade, reliability is everything. Moog designs with serviceability and endurance in mind. The two hexapods use the same motors and electronics, making spare parts and repairs simpler. The actuators can hold position even without power, protecting the optics if a system goes into standby. Built-in sensors monitor motor currents, bearing temperatures, and position drift, so maintenance teams get early warnings before issues grow.

These design choices mean the observatory can keep collecting hundreds of terabytes of science-grade images each year without constant human intervention.

Moog’s work on the James Webb Space Telescope (JWST) was a key reason we were chosen for Rubin. The hexapod design and build highly leveraged the work we did for JWST’s primary-mirror testing. While both programs had unique requirements, the actuators used the same drivetrain components, including motors, harmonic drive gear reducers, and roller screws, and much of the control software was reused. That heritage of reliability was a major factor in our selection to support the Rubin Observatory. We then refined those components to handle daily temperature swings, frequent slews, and the high-cadence imaging demands on Cerro Pachon.

Rubin’s survey will reveal fast transients, near-Earth objects, and subtle cosmic signals that help answer big questions about the universe and protect our planet. Moog’s role is to make sure each frame is as clear and reliable as possible. When the picture is precise, scientists can spot rare events, measure subtle effects, and trust the data that will inform discoveries for years.

Read our previous blog about the secondary-mirror installation milestone

Questions or interest in precision motion solutions for large-optics programs? Contact Moog at space@moog.com.