NASA's Roman Telescope Is Sharper Than Planned
NASA's newest big space telescope is doing better than its own designers hoped. Engineers working on the Nancy Grace Roman Space Telescope say its main camera now delivers image quality nearly 30% better than predicted.
Roman launched on August 30. Since then, teams at NASA's Goddard Space Flight Center in Maryland have been checking every part of it. They tested the 18 detectors of the Wide Field Instrument, each about the size of a sticky note. They also checked a rotating wheel of filters, a set of built-in LED lights used for calibration, and the system that keeps the instrument at the right temperature.
The telescope was already very well lined up when it reached space, thanks to careful testing on the ground. Only a tiny correction was needed. The team moved the secondary mirror by about one-sixteenth of the width of a human hair. One engineer compared it to adding less than the height of a single penny to the top of the Empire State Building.
That small nudge paid off. Before launch, the goal for optical error was about 90 nanometers. After the adjustments, engineers measured just 63 nanometers, well inside the target. The coronagraph, a second instrument built to block glare from bright stars, was also brought into focus and now meets the team's expectations.
Roman is designed to make wide surveys of the sky to study dark matter, dark energy and other big questions about the universe. Sharper images mean every one of those surveys should show more detail than planned. As one engineer put it, the cosmic surveys will be even sharper than expected.
