NASA’s Roman space telescope gets a new coronagraph to spot exoplanets

In a milestone event in October 2024, scientists at NASA’s Jet Propulsion Laboratory completed the integration of the Roman Coronagraph Instrument into the Nancy Grace Roman Space Telescope, an upcoming observatory scheduled to launch in May 2027. This highly advanced coronagraph can detect planets from up to 100 stars. million times fainter than their host stars, it is designed to block the light of stars and make the faint light of exoplanets visible. The integration marks an important step toward developing technology that could one day help NASA locate Earth-like planets in other solar systems.

Coronagraph instrumentation and technology demonstration

The Roman coronagraph, about the size of a baby grand piano, consists of an intricate system of masks, prisms and mirrors that work together to obstruct starlight. According to Rob Zellem, deputy project scientist for Roman Telescope Communications, the instrument is intended to demonstrate technologies crucial for future space telescopes, such as the proposed Habitable Worlds Observatory, designed to find life-supporting exoplanets. The Instrument Carrier, which houses the coronagraph, was attached to the Roman telescope at NASA’s Goddard Space Flight Center. This section, often described as the ‘skeleton’ of the observatory, will soon be integrated with Roman’s main science instrument, the Wide Field Instrument, completing the core of the telescope.

Exoplanet imaging: beyond traditional transit detection

Currently, most exoplanet discoveries rely on a method called transiting, which measures the dimming of a star when a planet passes in front of it. However, this technique is limited by the rare alignment of planetary orbits with Earth’s line of sight. Direct imaging, especially via coronagraphy, is an emerging method that allows scientists to observe planets without relying on transit events. While ground-based telescopes have had some success using coronagraphs, such as imaging planets orbiting the star HR 8799, the Roman coronagraph’s advanced design promises to achieve unprecedented sensitivity in space.

Next steps for NASA’s new telescope

Now that the coronagraph has been successfully integrated, NASA’s engineering team will conduct a series of system checks before installing the Wide Field Instrument later this year. Liz Daly, head of the Integrated Payload Assembly at Goddard, highlighted the joint efforts of several teams to bring the Roman Observatory closer to completion. The Roman telescope’s ability to investigate dark energy, exoplanets and infrared astrophysics will set a new standard in space observation.