The Nancy Grace Roman Space Telescope (Roman) will start operations in 2027. The Roman telescope will spend most of its time surveying large areas of the sky with a transformative Wide Field Instrument. Roman will also test new technologies for space-based exoplanet observations with direct imaging and spectroscopy, using the novel Roman Coronagraph Instrument (the Coronagraph hereafter).  The Coronagraph is a technology demonstration designed to prove a variety of flight hardware, software, and observational/data analysis techniques necessary to mature NASA’s ability to build a next-generation exoplanet characterization mission. The Coronagraph will provide visible light high-contrast imaging and is designed to be capable of directly detecting the reflected light from gas-giant-scale planets around nearby stars. Designed with many cutting-edge capabilities, the Coronagraph is by its nature experimental. The Coronagraph will achieve small-separation contrast ratios better than 10-7 and potentially up to 10-9 in visible light for the first time, exploring a new sensitivity regime.

NASA has created the Coronagraph Community Participation Program (CPP) to prepare for and execute Coronagraph observations.  The CPP is currently composed of several small, US-based teams, members of the Roman Project Team, and international partner teams from ESA, JAXA, CNES, and the Max Planck Institute for Astronomy. 

See the Coronagraph White Paper Resources page for further details on the technical specifications and expected capabilities of the Coronagraph.

The main goal of the Coronagraph is to validate technologies in space (wavefront control, high performance coronagraphs and ultra-low noise photon-counting detectors), that are relevant to the development of the Habitable Worlds Observatory (HWO). After commissioning is complete, the Coronagraph has a 3-month observing allocation (2,200 hours) within the first 18 months of the mission (henceforth referred to as the “observation phase”).  The program conducted during this allocation will not only verify the threshold technology requirements, but is also expected to include additional technology tests and execute cutting-edge exoplanet, circumstellar disk, and other high-contrast science observations. All data obtained by the Coronagraph during its observation phase and any potential period of extended observations will have no proprietary time.

Pending a successful initial demonstration of threshold technology requirements and additional high contrast science observations during the observation phase, the possibility exists that a further extended observing period with the Roman Coronagraph may be undertaken after the first 18 months of the mission.  An extended mission for the Coronagraph is not guaranteed, and is dependent on, among other factors, the strength of community interest as well as science case and technology demonstration arguments provided in the community white papers and by the CPP team.

In order to engage the coronagraph / exoplanet community in the definition of this observing program, the CPP is sponsoring a call for White Papers to define potential technology demonstration and scientific exploration observations during both commissioning and the observation phase and also during a potential period of extended observations.   The CPP is also interested in low contrast (worse than 10-7) observation ideas that might be appropriate for “first-look” Coronagraph observations early in the mission, prior to the Coronagraph achieving its full high-contrast performance.  This white paper call is intended to provide the main avenue for the community to influence observational priorities. The CPP solicits white papers describing both technology and scientific observing ideas.  All members of the community, across all career stages, positions, and types of institutions, are encouraged to submit their technology and science investigation ideas.

WHAT WILL HAPPEN WITH THE WHITE PAPERS?

White papers will be reviewed by members of the CPP team and will be used to inform the planning of the observation phase.  The CPP is responsible for developing and executing the Coronagraph observing plan, and will do so based on an internal process that evaluates the white papers as well as internal team priorities.  The CPP will review white papers based on their feasibility, their overall technological / scientific impact and their impact towards development of HWO. White papers should not be construed as observing proposals; the final set of observations will contain elements from many white papers as well as CPP team priorities. unless authors choose to opt-out, submitted white papers will be published on the CPP website and in some cases the CPP may reach out to specific white paper authors in 2026, should their further inputs be required to finalize observation planning.

WHO IS THE CORONAGRAPH CPP?

In preparation for the operational phase of the Nancy Grace Roman Space Telescope, NASA has created the Coronagraph Community Participation Program (CPP) to prepare for and execute Coronagraph Instrument observations.  The CPP is currently composed of several small, US-based teams, members of the Roman Project Team, and international partner teams from ESA, JAXA, CNES, and the Max Planck Institute for Astronomy.  The primary pre-launch goals of the CPP are to prepare tools, target databases, and data reduction software for the execution of the Coronagraph Instrument observation phase. The CPP’s core working groups focus on Observation Planning and Calibration, Data Reduction Pipeline (DRP) and Simulations, Hardware and Polarimetry. 

WHY SHOULD I SUBMIT A WHITE PAPER?

Coronagraph observations will be planned and executed by the CPP and the Coronagraph team. The CPP will also deliver a suite of publicly available, high quality data products to the community, including potentially the first direct image of a solar-system age giant exoplanet in reflected light. This white paper call provides the main opportunity for community members to provide input on the Coronagraph observing plan.  Additionally, an early demonstration of the strength of community interest and technology / science case arguments provided in the community white papers will be crucial for initial preparations for a potential extended mission review.

WHAT NEW TECHNOLOGY WILL THE CORONAGRAPH INCORPORATE TO ACHIEVE BETTER THAN 10-7 DETECTION LIMITS?

The Coronagraph will use active wavefront sensing and control in space for the first time through a pair of deformable mirrors working in concert, as well as a series of high-precision coronagraphic masks and two photon- counting electron-multiplying CCD (EMCCD) cameras.  This makes the Coronagraph an excellent technology demonstration for the Habitable Worlds Observatory (HWO) coronagraph instrument(s) which will rely on similar capabilities and subsystems. In addition, the Coronagraph will provide a unique system-level demonstration of active coronagraphy in space, allowing us to understand how all these subsystems interact together and with the overall observatory in the space environment.

WHERE CAN I FIND MORE INFORMATION ABOUT THE CORONAGRAPH?

Further information on the Coronagraph can be found on the resources page, with links to the Roman Coronagraph primer and technical documents (such as those hosted on the IPAC website).

WHO CAN I CONTACT ABOUT WHITE PAPERS?

If you have any questions about white paper submission, the LaTeX template, or the ETC, please send an email to roman.cpp.wp.submissions@gmail.com.