Engineers at NASA's Goddard Space Flight Center have completed a thorough testing campaign on the Roman Space Telescope's Wide Field Instrument, the primary tool for its planned cosmic surveys. The instrument's 18 detectors, each roughly the size of a sticky note, were examined alongside the electronics that operate them. The team also evaluated the element wheel, a rotating mechanism equipped with filters and other optical components that allow selected wavelengths of light to reach the detectors and can separate incoming light into individual colors.
"All of Roman's sweeping surveys will rely on the Wide Field Instrument," said Dave Hickey, a Wide Field Instrument systems engineer at NASA Goddard. "Many of the mission's primary goals, like studying dark matter and dark energy, wouldn't be possible without it, so it's both exciting and a huge relief to see that it's working well!"
Following the activation of the instrument in September, engineers tested the internal calibration system using light-emitting diodes that can produce different colors and brightness levels under commands from Earth. By measuring detector responses to these controlled signals, scientists can identify differences in sensitivity and apply corrections for accurate observations.
Engineers also tested the instrument's alignment mechanism, moving it from the deliberately unfocused position used during launch to the position expected to provide the sharpest images. They finished by checking the thermal control system, which maintains the required temperatures for various components.
"Calibrating an instrument is like tuning a piano or guitar before a concert," said Maxime Rizzo, a Wide Field Instrument systems engineer at NASA Goddard. "You adjust everything until it's just how you want it and then leave the settings alone so it performs consistently while you use it."
The Roman Space Telescope is designed to investigate dark matter, dark energy, and other cosmic mysteries. The improved image quality could help the telescope capture clearer images during its sweeping surveys of the universe.