The Roman Coronagraph Instrument

The Nancy Grace Roman Space Telescope is a NASA observatory designed to investigate essential questions in the areas of dark energy, exoplanets, and infrared astrophysics. The mission is managed by NASA's Goddard Space Flight Center in Greenbelt, Maryland. It carries one science instrument called the Wide Field Instrument, and one technology demonstration called the Roman Coronagraph Instrument.

Designed and built by NASA’s Jet Propulsion Laboratory, the Roman Coronagraph will advance scientists’ ability to directly image planets and disks around other stars (exoplanets). Coronagraphs work by blocking light from a bright object, like a star, so that the observer can more easily see a faint object, like a planet. The Roman Coronagraph is designed to detect planets 100 million times fainter than their stars, or 100 to 1,000 times better than existing space-based coronagraphs. The Roman Coronagraph will be capable of directly imaging reflected starlight from a planet akin to Jupiter in size, temperature, and distance from its parent star.

This capability is central to NASA’s next flagship astrophysics mission concept, the Habitable Worlds Observatory, which aims to image and characterize planets similar to Earth that orbit Sun-like stars.

The Roman Coronagraph will be the first active coronagraph to fly in space, meaning it contains components that actively respond to variables that would usually cause starlight to scatter, making it harder to see nearby planets. Its deformable mirrors, for example, will adjust for nearly imperceptible flaws in Roman’s optics, including its primary mirror. Missions such as NASA’s James Webb and Hubble space telescopes, by contrast, use passive coronagraphs that cannot change or adapt once they are operating.

In addition to developing and managing the Roman Coronagraph, JPL is assisting with testing detectors like those used in Roman’s Wide Field Instrument. JPL’s Precision Projector Laboratory (PPL) uses hardware and software to look for subtle effects in the Wide Field Instrument’s detectors that could impact performance. The PPL testbed rapidly generates a range of customizable “scenes” (for example, stars, galaxies, and spectra) on large-format detectors to uncover subtle systematic effects that can evade conventional detector testing. Once understood, detector issues can be mitigated via changes to hardware, calibration, mission operations, or data analysis. For more information, go to: https://arxiv.org/abs/1801.06599

JPL is also contributing to Roman’s core science goals by leading one of five Roman Project Infrastructure Teams that will develop measurement techniques necessary for Roman to reach its precision objectives with the Wide Field Instrument. The team, called “Maximizing Cosmological Science with the Roman High Latitude Imaging Survey,” will contribute to Roman’s study of dark matter and dark energy. Better understanding these two cosmological mysteries is part of the mission’s primary science goals using the Wide Field Instrument.

Coronagraph Instrument Fact Sheet

Nancy Grace Roman Space Telescope Mission Website