About this Article

Published December 16, 2025

The first General Astrophysics Survey for the Nancy Grace Roman Space Telescope has been fully defined through a community process: The Galactic Plane General Astrophysics Survey, a ~700 hour program, is expected to reach depths more than 10 times that of any previous infrared survey of the Milky Way’s disk plane, generate a catalog of approximately 20 billion sources, and measure proper motions for billions of stars.

It will enable investigations as varied as Galactic structure and dynamics, star formation, the interstellar medium, star clusters, evolved stars, low-mass stars and brown dwarfs, and the identification and characterization of compact binaries, free-floating planets, and eruptive and pulsating variables.

Defining Roman’s Galactic Plane General Astrophysics Survey

Roman’s General Astrophysics Surveys will enable science investigations beyond those that can be accomplished with Roman’s three Core Community Surveys. A General Astrophysics Survey of the Milky Way’s disk plane was recommended for early definition by a committee of scientists, following input from the broader science community (Sanderson et al., 2024). The definition of Roman’s Galactic Plane Survey followed a similar process as that for Roman’s Core Community Surveys, and had the same aim of soliciting and incorporating input from scientists around the world and optimizing the survey design to maximize its scientific potential. While the Galactic Plane Survey was defined through a community process, there will also be opportunities to propose PI-led General Astrophysics Surveys through a peer-review process, including in Roman’s first Call for Proposals, due March 17, 2026.

A definition committee was assembled with subject-matter experts representing the breadth of science reflected in the community input obtained from science pitches and white papers submitted in May 2024. An open virtual workshop held in February 2025 provided an additional opportunity for community input. The definition committee received technical and logistical support from Roman project partners (the Project Science Office at NASA Goddard Space Flight Center (GSFC), the Science Operations Center at STScI, and the Science Support Center at IPAC).

The committee began the effort of defining the ~700 hour program in September 2024 and submitted a report detailing their recommended implementation of the Galactic Plane Survey to the Roman Project in August 2025. Those recommendations were subsequently reviewed and endorsed by the Roman Observations Time Allocation Committee (ROTAC) in September 2025. The definition committee presented their recommendations at the October 1, 2025 Roman Community Forum. 

Survey Specifications

The recommended implementation of the Galactic Plane Survey consists of (1) a wide-field element, (2) a time-domain element, and (3) a deep-field and spectroscopic element.

The wide-field element will image approximately 700 contiguous square degrees, or ~35% of the surface area, of the Milky Way’s disk plane. The majority of the area will be imaged in four filters.

The time-domain element is comprised of six time-domain fields, covering 19 deg² in total, observed with varied cadences, each optimized for different science investigations.

The deep field and spectroscopic element will observe fifteen pointings (4.8 deg² in total) to greater depth than the wide-field imaging. These fields will be observed with all seven of Roman’s broadband filters (not including the F146 wide filter), the prism, and the grism.

The Galactic Plane Survey is expected to be completed within the first two years of the mission.

Great Opportunities Lie Ahead

Roman’s Galactic Plane General Astrophysics Survey is Roman’s fourth fully defined survey. The telescope’s three Core Community Surveys are also fully defined. (Read an overview of the process and a summary of the recommended implementations.) 

The surveys are designed to meet Roman’s science requirements while enabling broad astrophysical research. With science operations expected to begin early in 2027, now is the time to start planning how you will use the data from Roman’s community-defined surveys. Determine if Roman’s community-defined surveys will meet your needs — or if you should consider proposing another General Astrophysics Survey — by exploring the many resources available.

Resources

• Roman Galactic Plane Survey Definition Committee Report, Roman Galactic Plane Survey Definition Committee, 2025
• RDox article describing the implementation of Roman’s Galactic Plane Survey