Roman Space Telescope Powers Up 300-Megapixel Camera in Space

NASA's Nancy Grace Roman Space Telescope has successfully activated its Wide Field Instrument, a 300-megapixel infrared camera built to survey vast areas of the universe while capturing fine detail. The telescope's Coronagraph Instrument has also completed an early checkout of its digital, electronic, and mechanical systems. Together the milestones move Roman closer to beginning science operations in 2027.

The tests are part of a months-long commissioning process that continues as Roman travels roughly one million miles toward its destination at the second Lagrange point, L2. The Wide Field Instrument, or WFI, combines an unusually broad view of the sky with the sharp detail associated with space telescopes such as NASA's Hubble. A single WFI image will cover an area of sky larger than the apparent size of a full moon, allowing Roman to carry out enormous surveys aimed at studying planets beyond the solar system, investigating dark energy, and mapping how matter is arranged across the universe.

Before engineers could switch on the WFI, the instrument spent 10 days drying out and undergoing decontamination, with its detectors held at minus 85 degrees Fahrenheit. On the morning of September 11, the team shut off the instrument heater and allowed the WFI to cool to minus 225 degrees Fahrenheit, at which point engineers activated Roman's 18 infrared detectors. Those detectors together have a light-sensitive area roughly the size of a laptop screen. Later that evening the team turned on the calibration system, and the following morning engineers began sending test data through the WFI back to Earth.

Over the weekend, engineers tested the element wheel, which contains filters, prisms, and other optical components that control which wavelengths reach the detectors. It marked the first time the mechanism had been tested without gravity. By Sunday the team was testing the focusing mechanism, which will keep Roman's hundreds of thousands of images properly focused as the detectors continued cooling toward their final operating temperature of about minus 300 Fahrenheit.

"After years of effort to build and test the instrument on the ground, we now have confirmation that it is operational in space. This is a huge milestone for the team at Goddard, our industry teams at BAE Systems, Inc. and Teledyne, and our science centers," said Josh Schlieder, the Wide Field Instrument scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "There is much to do, but we are on our way to groundbreaking science."

The Coronagraph Instrument, built to demonstrate advanced technology for directly imaging planets around other stars, also passed early checks. Teams at the Coronagraph Commanding Center at Caltech/IPAC in Pasadena, California, verified they can communicate with every major part of the instrument, including its software, thermal controls, mechanisms, cameras, and avionics. Engineers confirmed the thermal system can warm the hardware to its operating temperature of 72 degrees Fahrenheit. With the exception of its detectors, the coronagraph is designed to operate near room temperature, which helps preserve the material properties required by its deformable mirrors.

The results confirmed the Wide Field Instrument is functioning as expected, and Roman remains on schedule to release its first science images by early 2027.

The coronagraph is now decontaminating, sitting idle with its detectors warm to shed water or trace chemicals. "This will continue for 30 days, with occasional stops to do other early calibration activities," said Eric Cady, an optical engineer leading commissioning efforts for the Roman Coronagraph at NASA's Jet Propulsion Laboratory in Southern California.