NASA’s Roman Space Telescope has entered its final commissioning phase before it starts science

NASA’s Nancy Grace Roman Space Telescope has entered the science commissioning phase, the last stretch of preparation before it begins its scientific work. The agency announced the step on Oct. 22 after the team finished a comprehensive checkout and refinement of the observatory and its primary instrument. Mission scientists say the spacecraft is fully functional.

Stay ahead on AI: Join 600,000+ professionals who read The Deep View, the daily newsletter that keeps you up to date with artificial intelligence.

Subscribe to The Deep View →

We may earn a commission if you sign up.

That status covers the basics a telescope must do before it can observe anything: guide itself, take exposures, handle the flow of data and slew between targets. The next weeks are for tuning rather than troubleshooting, and early results suggest some systems are performing better than the mission requires, which NASA says could open new scientific capabilities. Commissioning, in other words, is where a spacecraft that passed its ground tests proves it can do the same job in orbit, and Roman has now cleared the first two checkpoints of that proof.

The commissioning phase that follows checkout

Julie McEnery, the Roman senior project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, said in the agency’s Oct. 22 update that the team has established that the observatory is fully functional and is now turning to fine details of image quality. The team is running planned test observations to characterize performance and to calibrate how the instruments respond to light, before moving into science operations.

The post does not give a date for the start of routine science, and it does not say how long this phase will last. NASA’s commissioning page for the mission describes commissioning as the time when scientists and engineers make sure Roman is performing as expected, and says the schedule may change as the team assesses progress. The same page describes a three-month journey to the second Sun-Earth Lagrange point, known as L2, during which this work takes place. The agency’s wording leaves room for change, so readers should treat any target for first science images as unannounced until NASA names one.

Roman rose from Launch Complex 39A at Kennedy Space Center in Florida aboard a SpaceX Falcon Heavy on Sunday, Aug. 30, 2026, according to a photo gallery of the launch.

Guidance and the Wide Field Instrument

One worry before launch was whether the fine guidance system would struggle in crowded or dusty regions. Tom Barclay, Roman’s operations project scientist at Goddard, reported that it performed well when pointed at dense star fields and dust-obscured nebulae. Jeremy Perkins, the observatory integration and test scientist, said he was impressed by the detail Roman captures in short exposures during these test observations, a sign that the telescope can gather useful data quickly even before final tuning is finished.

The Wide Field Instrument is the main survey camera, and NASA says that in a typical observation it can detect objects about a hundred million times fainter than the human eye can see. Josh Schlieder, the instrument’s scientist at Goddard, said even very small flaws could hide the faint signals the mission aims to measure, which is why calibration takes so much attention. NASA expects its fast survey speeds to make large mosaics routine and rare sightings more common.

The reason for that precision is on NASA’s Roman mission page. The telescope is meant to settle questions about dark energy, exoplanets and infrared astrophysics, it could measure light from about a billion galaxies over its lifetime, and its field of view will be at least 100 times larger than Hubble’s. Surveys on that scale only work if every detector responds the same way to the same light, which is exactly what the calibration observations now under way are meant to confirm across the camera’s whole field.

Numbers from the earlier checkout

An Oct. 14 NASA post on the instrument checkout and focus work supplies the measurements behind that confidence. The team activated the Wide Field Instrument in September and tested its 18 detectors and their electronics, the element wheel that holds filters, the internal calibration LEDs, the alignment mechanism and the thermal system that keeps components at the proper temperatures.

The instrument’s image-quality requirement was about 90 nanometers of error, measured as root mean square. After the corrections, its optics have an error of 63 nanometers, which NASA says is nearly 30% better than the team predicted. Alden Jurling, a senior optical engineer, said the images from Roman’s cosmic surveys will be even sharper than expected.

Reaching that sharpness meant moving the secondary mirror by about one-sixteenth of the diameter of a human hair, according to Jurling. Matthew Bolcar, the optical systems lead, explained why such fine adjustments were needed: ground testing could not exactly reproduce the environment Roman would experience in space. Maxime Rizzo, a systems engineer on the instrument, compared calibration to tuning a piano or guitar before a concert.

The Coronagraph Instrument team still has work ahead. Its early images were slightly out of focus, and its camera settings and deformable mirrors need calibration before the team plans to demonstrate its light-blocking capability in the coming weeks, according to the Oct. 14 post.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

Stay ahead on AI: Subscribe to The Deep View →

We may earn a commission if you sign up.