Legacy Survey of Space and Time Camera
Scientists could be one step closer to understanding some of the biggest mysteries of the universe as the world’s largest digital camera makes its way to the Vera C. Rubin Observatory in Chile. Nearly six years in the making, the camera is the nerve center of the Legacy Survey of Space and Time (LSST), a 10-year initiative to provide the “widest, fastest and deepest views of the night sky ever observed.” The goal? Gain knowledge about everything from dark matter to the Milky Way.
Roughly the size of a small SUV and weighing more than three tons, the one-of-a-kind US$168 million camera required a team effort, with two U.S. Department of Energy facilities leading the charge from California. SLAC National Accelerator Laboratory is managing the camera’s fabrication, while Lawrence Livermore National Laboratory is designing the major optical components.
“The challenge in a project like this—where you’re creating something that’s never been done before—is overcoming the doubt of if the project is even possible,” says Vincent Riot, LSST camera manager and engineer at the Lawrence Livermore National Laboratory. “You need a lot of discipline.”
Like any standard-issue digital camera, the LSST version is made up of many electronic imaging sensors. But to ensure the camera’s ultra-precise focusing capabilities in a wide field of view and with rapid repointing, the team had to invent new electronic sensors that are larger, more sophisticated and thin enough to sit in the camera’s flat focal plane. This allows the camera to capture images more than 40 times the area of the full moon in the sky with each exposure and to do so in mind-bogglingly high resolution—such that it would take 1,500 high-definition TV screens to display just one picture. Oh, and the team also had to make it durable enough to deliver all that data with minimal downtime and maintenance.
Assembling the fragile array of nearly 200 sensors at SLAC took six nerve-wracking months. To avoid destroying the delicate components during installation, the team iterated designs for a robot that could assemble the bundles of sensors and electronics with machine precision. And to prevent components from overheating, the team created a custom refrigeration system to redirect heat and installed filter dryers to absorb excess moisture.
Another issue? Chile’s COVID-19 restrictions blocked nonresidents from the observatory site, which forced the team building the telescope—upon which the camera will sit—to shift some tasks to alternative locations and workers. All of that pushed out the timeline by about two years.
But soon the camera will reach its destination some 8,800 feet (2,682 meters) high in the Andes Mountains. There, the 3.2-gigapixel camera will capture a 15-second exposure of the sky every 20 seconds for 10 years. That’s 15 terabytes of data per night—which will help scientists map around up to 20 percent of galaxies in the observable universe.
“What keeps you going through all that is the knowledge that, when we’re done, we’ll have built this thing that’s not only unique in the world, but will produce this data set that will probably still be analyzed for 100 years,” says Steven Kahn, Rubin Observatory director. “We’re mapping the universe for the first time.”
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