Set to launch on Sunday, Aug. 30, NASA’s Nancy Grace Roman Space Telescope will empower astronomers to explore vast regions of the cosmos and settle essential questions in the areas of dark energy, dark matter, planets outside our solar system, and the formation and growth of galaxies over cosmic time. Key contributions to Roman’s mission made by researchers at NASA’s Ames Research Center in California’s Silicon Valley will advance Roman’s science using the center’s facilities, expertise, and innovations.

Tools to predict, remove glare

Roman’s main camera, the Wide Field Instrument, will capture expansive high-resolution pictures of the universe in optical and near-infrared light. These unprecedented images will enable astronomers to decode some of the deepest mysteries of the cosmos.

Forms of glare that Roman’s camera collects diminish image quality and thereby reduce the ability of astronomers to characterize certain cosmic structures. Innovative software developed by a team at NASA Ames, with collaborators at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and IPAC/Caltech in Pasadena, California, will improve Roman’s images and optimize observing plans. Called ROSALIA (Roman Sky Analyst for Low Surface Brightness Imaging and Astronomy), the software predicts and removes unwanted light from astronomical images captured by Roman’s Wide Field Instrument.

Contaminating stray light occurs when photons scatter inside the telescope’s optical system. Resulting light glints can produce deceptive image artifacts that mimic the appearance of real planets or nebulae. The ROSALIA software will allow astronomers to adjust their observation plans to limit glints from contaminating science targets in Roman’s images.

In addition to bright glints, stray light can also appear as a diffuse background. This form of stray light interferes with observations of the darkest regions of the universe, which is critical to understanding how large structures in the universe were formed.

Another major contributor to obscuring background light is produced by nature itself: zodiacal light. Zodiacal emission originates from the scattering of sunlight by interplanetary dust particles in our solar system. The ROSALIA software predicts and strips away background contamination, including zodiacal and stray light from images, exposing the faint, diffuse emissions at galaxy edges where cosmic evolutionary histories are hidden.

New ‘multi-star’ tech to see exoplanets

The Roman Coronagraph Instrument is one of two instruments flying on Roman. It will demonstrate the most advanced technologies ever flown in space for directly imaging planets around other stars. The Roman Coronagraph uses a series of masks and mirrors, including two deformable mirrors, to suppress starlight. By precisely controlling the shape of the deformable mirrors, it creates a “dark zone” around the star where observers can see the faint reflected light from orbiting planets.

The baseline operating mode of the Roman Coronagraph Instrument supports observation of exoplanets only in single star systems, as current coronagraph instruments cannot typically suppress the additional contaminating starlight in multi-star systems, such as binary star systems.

Our solar system has a single star, the Sun. But roughly half of Sun-like stars are in multi-star systems. Having the ability to directly image exoplanets in multi-star systems will increase the likelihood of detecting life beyond our solar system and will expand our knowledge about how exoplanets form and evolve, since there are major differences in how those processes unfold in single star versus multi-star systems. Eliminating overlapping glares from multiple stars is the key challenge that must be overcome to image planets in such systems.

Researchers at NASA Ames are meeting that challenge with an innovative technology called Multi-Star Wavefront Control (MSWC). This technology includes custom light-blocking masks and accompanying software designed to suppress the light from multiple stars and reveal hidden exoplanets. Through a collaboration with NASA’s Jet Propulsion Laboratory in Southern California, the MSWC masks are included on the Roman Coronagraph’s flight instrument as an added capability beyond Roman’s baseline observation modes. They could be used if additional observation time is granted to the coronagraph team after the primary technology demonstration phase is completed. 

The nearest star system to our solar system, Alpha Centauri, is one of the nearest multi-star systems to Earth,  at only four light-years away. This triple-star system contains a binary of Sun-like stars – Alpha Centauri AB – orbited by a much smaller and dimmer star – Proxima Centauri. Although no exoplanets are confirmed around the Sun-like stars in this system, a planet candidate has been identified by NASA’s James Webb Space Telescope in the habitable zone of Alpha Centauri A. Researchers, including the Ames MSWC team, are working to develop the capabilities needed to observe this system.  

NASA Ames also provides leadership and support for the hardware working group as part of the Roman Coronagraph Participation Program. This program allows international teams of researchers to enable additional capabilities to the Roman Coronagraph beyond its baseline modes; this includes the multi-star modes being developed at NASA Ames that use different masks beyond the baseline or new wavefront control and sensing algorithms.

Advanced supercomputing

Experts at NASA’s Advanced Supercomputing Division at Ames are advancing Roman’s science by bringing extensive experience in data pipelines and mission operations to provide advice and guidance to the Roman project through key mission development phases. This ensures reliable performance of ground-based systems and operations so that science data processing is efficient and the quality and integrity of the resulting science data products is high.

NASA Advanced Supercomputing researchers collaborated with the Ames MSWC team to develop high-performance computing tools for multi-star wavefront control simulations and to conduct studies to assess the feasibility of the MSWC technique.

Learn more:

The Nancy Grace Roman Space Telescope mission: https://science.nasa.gov/mission/roman-space-telescope/

For news media: 

Roman media resources: https://science.nasa.gov/mission/roman-space-telescope/roman-media-resources/

Members of the news media interested in covering this topic should reach out to the NASA Ames newsroom.