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Unique Lift System Enables Installation and Servicing of Telescope Mirrors
Everything About the LSST Is Big!
The Vera C. Rubin Observatory (formerly the Large Synoptic Survey Telescope, LSST), constructed atop the 8,737-foot El Peñón peak in northern Chile, is a partnership project of the National Science Foundation (NSF) and the United States Department of Energy (DOE).
Project Results at a Glance
- Enabled safe lifting of a 90+ ton mirror system
- Supported the final construction of the Rubin Observatory
- Continues to support ongoing maintenance and servicing
The goal of the Rubin Observatory is to conduct a 10-year survey that will deliver a 200-petabyte set of images and data addressing some of the most pressing questions about the structure and evolution of the universe and the objects within it.
A Telescope Built for Big Data
The Rubin Observatory conducts a deep survey over an enormous area of sky and does so with a frequency that enables images of every part of the visible sky to be obtained every few nights. This mode will continue for 10 years to achieve astronomical catalogs thousands of times larger than have been previously compiled.
The Rubin Observatory is now one of the world’s most powerful survey telescopes. It is a wide-field survey reflecting telescope with an 8.4-meter primary mirror. It is unique among large telescopes because of its very wide field of view of 3.5 degrees, covering a 64-cm-diameter flat focal plane. It uses a novel three-mirror design that delivers sharp images feeding a 3.2-gigapixel CCD imaging camera — the largest digital camera ever constructed.
Unprecedented Imaging Capabilities
The camera takes a 15-second exposure of the night sky every 20 seconds, 800 panoramic images every night. That is equivalent to taking roughly 800,000 images with an eight-megapixel digital camera, but of much higher quality — more than 200,000 exposures per year of raw image data. The10-year survey will allow the Rubin Observatory to produce a deep, time-dependent, multi-color movie of the sky.
Initial computer requirements are estimated at 100 teraflops of computing power (one teraflop is a measure of computing speed equivalent to one trillion floating point operations per second). The camera contains more than three billion pixels of solid-state detectors. More than 30 terabytes of data are processed and stored each night to produce one of the largest non-proprietary data sets in the world.
By digitally imaging the sky for a decade, the Rubin Observatory produces a petabyte-scale database enabling new paradigms of knowledge to address the most pressing questions in astronomy and physics that are driving advances in big data science and computing.
The observatory reached a major milestone in 2025 with the release of its first full-resolution images, marking the completion of decades of design and construction. Early observations have already identified millions of galaxies and thousands of previously unknown asteroids.
DESIGN LIMITATIONS FOR A MIRROR LIFT SYSTEM
The methods devised to safely transfer these very large, heavy, and extremely critical optics from the telescope to the coating plant vary widely for different telescope facilities. Cranes mounted on domes conveying the mirrors through floor hatches, custom screw-post lifts within the enclosures, special trucks with jacking beds to lift and transport the mirrors, and even bringing the coating plant to the telescope have all been utilized at telescopes designed and built in recent decades.
The wide support pier for the Rubin Observatory telescope, however, did not allow space for lifts or hatches to be located within the telescope chamber that would be large enough to convey the primary mirror assembly, which is 27 feet in diameter and weighs in excess of 93 tons.
Adding to the design challenge, the mirror transporting method was required to operate within a seismically active zone, safely absorbing seismic loads of up to 8.0 on the Richter scale, as well as resist 100-mph wind loads present on the mountaintop. Further, because the site’s elevation is at 8,737 feet above sea level, the system needed to be factory pre-constructed and tested, disassembled for shipping within containers, and reassembled onsite at the observatory facility.
ENGINEERING CHALLENGE
The use of a vertical reciprocating conveyor (VRC) was identified as a viable option for the mirror transporting system, although there were no known precedents for using a VRC to transfer large telescope mirrors. In 2010, PFlow Industries was engaged to conduct an engineering analysis for the design of a VRC solution for the lift.
“Designing a building to support the lift, and simultaneously resist the wind and seismic forces, proved to be difficult,” said Jeffrey Barr, Project Architect. “It was decided early on to incorporate the lift structure into the building design through collaboration between PFlow structural engineers and the Chilean structural engineers designing the facility.”
The PFlow solution was a permanently installed lift outside of the telescope dome enclosure, integrated within the building structure itself, rising to the level of the dome to receive the payload of the mirror assembly through a back entry door.
During normal telescope observing operation, all elements of the lift and shaft retract below the dome to stay out of the way of its rotation and out of the observing field of view of the telescope. This required the lift to raise the shaft roof when deployed to its upper position to receive the mirror from the telescope and deliver it back after recoating.
The 80-foot-high lift also needed to be extremely reliable and flexibly designed to transport other large loads to various levels of the observatory facilities.
PFlow Industries designed and delivered the custom lift system that enabled the final installation of the telescope’s mirror assembly—one of the most critical stages of the project.
INNOVATIVE LIFT DESIGN
PFlow engineers leveraged and extended existing well-proven industrial technology for this specialized application. Many features were incorporated to protect the mirror assembly during transport, and all critical lifting components include redundancy to minimize the chance of a catastrophic failure.
Key System Specifications
- Lift capacity: 93+ tons
- Platform size: 35 ft x 35 ft
- Lift height: approximately 80 ft
- Structural steel: ~160,000 lbs
The lifting carriage consists of a 35 × 35-foot platform, supported by an 11-foot-tall structure beneath it.
The lifting system was designed such that the failure of any single lift system component would not result in a loss of control of the load. Twelve lifting chains, powered by a pair of 60-HP gear drives weighing 6,500 pounds each, are incorporated with a combined tensile strength of 974 tons.
“Roller chain drives inherently have some vibration due to the chordal action of the chain as it is driven by the sprocket,” added Mark Webster, PFlow’s now retired VP of Engineering. “A new chain drive arrangement (patent-pending) was engineered to eliminate this chordal action, resulting in a linear carriage velocity and ensuring smooth platform velocity.”
Two redundant motor/gear-reducer/brake assemblies are provided and synchronized. A single brake has adequate torque to support the entire load independently.
The lift platform is locked at each level to allow for the smooth transfer of the mirror aboard a wheeled cart riding on rails. A variable frequency drive ensures precise, low-impact positioning when engaging platform locks.
A guide system allows the carriage to extend above guide columns and lift a 20,000-pound observatory roof section 15 feet vertically, with integrated safety locks to protect against seismic and wind events.
LSST CONSTRUCTION PROJECT
The construction project was funded by the NSF and DOE, both of which now support the ongoing operation of the observatory.
Site excavation began in March 2011, followed by construction of the telescope facility in January 2015. By 2018, the facility was substantially completed. The vertical reciprocating conveyor was fully completed, installed, and tested, and was successfully used to transport and install critical telescope components, including the mirror system.
The lift played a key role in raising major telescope components multiple stories into the dome during final assembly and now remains in place to support ongoing maintenance and servicing operations.
The observatory has captured its first scientifically usable data (science first light) and is now actively conducting its 10-year survey mission.
The Result
PFlow’s custom lift solution enabled the safe, precise installation of one of the most critical components of the Rubin Observatory while overcoming extreme environmental and structural constraints.
Today, the lift remains an integral part of the facility, supporting ongoing maintenance and long-term operation of one of the world’s most advanced astronomical observatories.
Why It Matters
Projects like the Rubin Observatory demonstrate how advanced material handling solutions play a critical role in enabling scientific discovery. Without reliable, high-capacity lifting systems, the installation and maintenance of massive, high-value components would not be possible.
Conclusion
PFlow Industries delivered a highly specialized lifting solution that met the unique demands of this landmark project. From initial installation through ongoing operation, the system continues to support the performance and longevity of a world-class scientific instrument.
Need a custom lifting solution for a complex application? Contact PFlow Industries to learn more about our vertical reciprocating conveyors and engineered systems.