NASA is preparing to launch its next major space observatory, designed to help scientists explore some of the universe’s biggest mysteries, including dark energy and dark matter. The observatory will also test gravity over vast distances and search for exoplanets beyond our solar system.
The Nancy Grace Roman Space Telescope, a project with a price tag of around $4 billion, is scheduled to launch this Sunday from NASA’s Kennedy Space Center in Florida. It will be carried into orbit aboard a SpaceX Falcon Heavy rocket. Notably, this launch is nine months earlier than initially planned, according to NASA officials.
Roman is considered the successor to both the Hubble Space Telescope, launched in 1990, and the James Webb Space Telescope, launched in 2021. It has advanced capabilities that will build upon the knowledge gained from these pioneering observatories, both of which remain operational.
With its wide-field view of space and rapid surveying ability, Roman provides an unprecedented opportunity for scientists to study the cosmos. It will examine the structure, composition, and evolution of the universe through large-area surveys.
Roman’s primary goal is to uncover the unusual, rare, and mysterious phenomena scattered across the universe, according to Julie McEnery, the project’s lead scientist at NASA’s Goddard Space Flight Center. She emphasized that the telescope’s combination of high sensitivity and speed will facilitate extensive sky surveys covering over two billion galaxies. This will enable researchers to better understand how cosmic structures—stars, galaxies, galaxy clusters—formed and evolved, as well as how the universe’s expansion has changed over time. Such insights are vital for deciphering the true nature of dark matter, dark energy, and the fundamental fabric of the universe.
The universe originated about 13.8 billion years ago with the Big Bang, and it has been expanding ever since. In 1998, scientists discovered that this expansion is accelerating, driven by an invisible force called dark energy.
The universe’s content includes ordinary matter—stars, planets, gas, dust, and familiar earthly substances—as well as dark matter and dark energy, whose true nature remains largely unknown. Ordinary matter makes up roughly 5% of the universe, dark matter about 27%, and dark energy approximately 68%.
Mustapha Ishak, a cosmologist from the University of Texas at Dallas and a member of the Roman team, explains that a key question is whether dark energy is a fixed property of empty space or if it evolves over time. Recent findings from the Dark Energy Spectroscopic Instrument (DESI) suggest there may be signs of dark energy changing over cosmic time. Understanding whether the universe’s acceleration stems from modifications to gravity on large scales is one of the most critical questions in modern cosmology.
Roman will also study how galaxies cluster and how mass bends light, a phenomenon known as gravitational lensing. These measurements will test Einstein’s general theory of relativity—formulated in 1915—over billions of light-years. If deviations are observed, it could point to the need for new physics governing gravity on the largest scales, addressing fundamental questions about the laws that shape our universe.
In addition to cosmic exploration, Roman will conduct one of the most extensive searches for exoplanets ever undertaken. It is expected to discover thousands of new planets and provide statistical data on planetary systems similar to our own. The telescope will also demonstrate advanced technology for directly imaging exoplanets near Earth.
After its launch, Roman will travel to a location known as Lagrange Point 2, roughly a million miles (about 1.6 million kilometers) from Earth—about four times farther than the Moon. This orbit is similar to that of the James Webb Space Telescope, whereas the Hubble resides in low Earth orbit.
The mission is planned for five years, though NASA indicates it could operate for an additional five years if it has enough fuel. Despite attempts by the Trump administration to cut or defund the project during both its first and second terms, Congress upheld its funding. The telescope is named after Nancy Grace Roman, NASA’s first chief astronomer, who passed away in 2018 at age 93.