At the heart of our galaxy lies a dense congregation of stars, surrounding a supermassive black hole. NASA’s Nancy Grace Roman Space Telescope is set to provide the deepest-ever view of this enigmatic region, potentially uncovering stars, planets, and other celestial phenomena that defy current definitions.
Drawing on the expertise of astronomers worldwide, the Roman Space Telescope will dedicate three-quarters of its five-year primary mission to three groundbreaking surveys of unprecedented scope. These surveys aim to revolutionize our understanding of astronomy and address longstanding mysteries about dark matter, dark energy, and exoplanets—planets beyond our solar system.
Galactic Bulge Time-Domain Survey: A Closer Look
The Galactic Bulge Time-Domain Survey will focus on the densely populated region near the center of the Milky Way, known as the galactic bulge. Over 438 days of observation, the survey will monitor six specific areas, including the galactic center, at 12-minute intervals. This meticulous approach will allow scientists to observe changes in the motion and luminosity of hundreds of millions of stars and any orbiting planets, highlighting the “time-domain” aspect of the survey.
“This survey will be the highest precision, highest cadence, longest continuous observing baseline survey of our galactic bulge, where the highest density of stars in our galaxy reside,” said Jessie Christiansen of Caltech/IPAC, co-chair of the committee that defined the survey.
Exoplanet Microlensing: A New Frontier
Roman will employ a technique known as microlensing to search for exoplanets. This method, which has identified just over 200 exoplanets to date, is expected to discover over 1,000 new planets in this survey alone, increasing the number identified by microlensing more than fivefold.
A microlensing event occurs when the light from a distant star is warped by a foreground object, such as a star and its planet, due to gravitational lensing. This method is particularly effective for detecting exoplanets that orbit at greater distances from their stars, offering insights into planetary systems farther from Earth than previously studied.
“For the first time, we will have a big picture understanding of Earth and our solar system within the broader context of the exoplanet population of the Milky Way galaxy,” Christiansen noted. “We still don’t know how common Earth-like planets are, and the Roman Galactic Bulge Time-Domain Survey will provide us with this answer.”
Beyond Exoplanets: A Wealth of Scientific Discovery
The survey’s extensive observing time and data will not only advance exoplanet microlensing but also other areas of astronomy. According to Dan Huber of the University of Hawaii, the survey’s co-chair, “There is an incredibly rich diversity of science that can be done with a high-precision, high-cadence survey like this one.”
Optimized for microlensing, the survey will also track changes in brightness, enabling the discovery and characterization of transiting planets, red giant stars, stellar-mass black holes, and eclipsing binaries. This will deepen our understanding of star formation and evolution.
“The stars in the bulge and center of our galaxy are unique and not yet well understood,” Huber explained. “The data from this survey will allow us to measure how old these stars are and how they fit into the formation history of our Milky Way galaxy.”
Preparing for Launch: The Road Ahead
The Roman Science Support Center at Caltech/IPAC in Pasadena, California, will handle high-level science data processing for the survey, including exoplanet microlensing and community outreach. Automated monitoring will detect microlensing and variable events, aiding scientists in understanding stellar brightness changes and potential planetary presence.
All Roman observations will be publicly available after processing, with the mission scheduled to launch no later than May 2027. The team is on track for a fall 2026 launch.
The Nancy Grace Roman Space Telescope is managed by NASA’s Goddard Space Flight Center, with contributions from NASA’s Jet Propulsion Laboratory, Caltech/IPAC, the Space Telescope Science Institute, and a team of scientists from various institutions. Primary industrial partners include BAE Systems Inc., L3Harris Technologies, and Teledyne Scientific & Imaging.
As the launch date approaches, the anticipation builds for the wealth of knowledge the Roman Space Telescope promises to unlock, potentially reshaping our understanding of the universe and our place within it.
