Summary

NASA has activated the Nancy Grace Roman Space Telescope’s Wide Field Instrument, a 300-megapixel infrared camera, and completed an initial test of its coronagraph. The observatory remains in commissioning, with first science images expected by early 2027.

NASA has activated the Nancy Grace Roman Space Telescope’s primary science instrument, a 300-megapixel infrared camera designed to survey wide areas of the sky while preserving the fine detail associated with space telescopes such as Hubble. The mission team has also completed an initial checkout of Roman’s Coronagraph Instrument, which is intended to demonstrate technologies for directly imaging planets around other stars.

The milestones were announced by NASA on September 15, 2026, during Roman’s continuing commissioning phase. The spacecraft is travelling toward the second Lagrange point, or L2, while engineers carry out months of calibrations and tests.

Contents

Roman’s wide-field camera comes online

The Wide Field Instrument, or WFI, contains 18 infrared detectors with a combined sensing area about the size of a laptop screen. NASA says each image will cover a region of sky larger than the apparent size of the full Moon, with the sharpness needed for detailed astronomical observations.

That combination of field of view and resolution is central to Roman’s mission. Its surveys are intended to help astronomers investigate planets beyond the solar system, study dark energy, and map how matter is distributed across the cosmos. The same broad, high-resolution data set is also expected to support a wide range of additional studies.

The activation followed a carefully staged cooling and checkout process. The instrument first remained inactive for 10 days to dry out and remove contamination while its detectors were held at minus 85 degrees Fahrenheit, or minus 65 degrees Celsius. On September 11, engineers switched off the heater and allowed the WFI to cool to minus 225 F, or minus 143 C, before activating the 18 detectors. They will eventually operate at about minus 300 F, or minus 183 C.

Engineers then activated the calibration system and sent test data through the instrument to ground teams. They tested the element wheel, which carries filters, prisms and other optics that control the wavelengths reaching the detectors and separate light from cosmic objects into colours. The focus mechanism was also tested in space, an important step because it will focus the hundreds of thousands of images the instrument is expected to take.

The first image is an instrument test

The first starlight image from the WFI shows a field filled with deliberately out-of-focus stars. The detector array was still stowed in its launch configuration and was far from its final focus, so each star’s light spread across many thousands of pixels.

This is an initial performance assessment rather than a finished astronomical observation. The image gives the Roman team a starting point for aligning the telescope’s optics and tuning the focus. NASA says the instrument’s fine-guidance system will be activated next so the observatory can lock onto targets. Once the telescope is focused, stars should appear as sharp points instead of the broad, donut-like features visible in the test image.

NASA expects to release Roman’s first science images by early 2027. The latest checks confirmed that the WFI is working as expected, but the instrument is still moving through its calibration and commissioning programme.

Coronagraph checkout prepares for exoplanet imaging

Roman’s Coronagraph Instrument is designed to block the intense glare of a star so that much fainter light reflected by planets orbiting it can be detected. It combines masks, deformable mirrors, optics and sensors. The masks modify the diffraction pattern of starlight, while the deformable mirrors can adjust the wavefront to improve contrast between a star and nearby planets.

During the initial test, teams at the Coronagraph Commanding Center at Caltech/IPAC confirmed communication with the instrument’s software, thermal controls, mechanisms, cameras and avionics. They also checked the movable systems that hold its masks, colour filters, lenses and prisms.

The coronagraph’s thermal control was tested by warming its hardware to an operating temperature of 72 F, or 22 C. Apart from its detectors, the instrument is designed to operate near room temperature. NASA said the coronagraph will now undergo a 30-day decontamination period with its detectors warm, allowing water or trace chemicals on the surfaces to leave the instrument. Other early calibration activities will take place during scheduled pauses.

Together, the two milestones move Roman from a spacecraft that has reached its destination environment toward an observatory capable of producing calibrated scientific data. The WFI will provide wide surveys across the infrared sky, while the coronagraph will test methods for suppressing starlight and studying planetary systems that are otherwise difficult to observe directly.

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