The Roman Space Telescope Is Ready to Fly

If you follow space news at all, you’ve probably heard about the James Webb Space Telescope and the incredible images it’s been delivering since 2022. But NASA’s next flagship observatory is already built, fully tested, and headed to the launch pad. What it’s about to do for astronomy might be even more transformative than what Webb has accomplished so far.

The Nancy Grace Roman Space Telescope is targeted for launch in early September 2026 aboard a SpaceX Falcon Heavy rocket. NASA Administrator Jared Isaacman revealed the timeline at an April 21 event at the agency’s Goddard Space Flight Center in Greenbelt, Maryland, where the assembled telescope was shown to the public for the first time. That September date puts the mission a full eight months ahead of its official deadline and under budget.

So what exactly is the Roman Space Telescope, and why should you be excited about it? 

At the heart of the Roman Space Telescope sits a 2.4-meter (7.9-foot) primary mirror. That’s the same diameter as the one inside the Hubble Space Telescope. But where Hubble looks at the universe through what amounts to a narrow straw, Roman takes in the cosmos through something closer to a picture window. Its Wide Field Instrument, a 300-megapixel infrared camera, captures a patch of sky more than 100 times larger than what Hubble'’ imaging cameras can see in a single exposure.

Roman can survey the sky more than 1,000 times faster than Hubble. The images Roman captures will be so large that no screen currently in existence is big enough to display one at full resolution. Over its five-year primary mission, Roman is expected to observe more than 100,000 exoplanets, hundreds of millions of galaxies, and billions of individual stars. The telescope will generate roughly 500 terabytes of data per year, more than Hubble has produced across its entire 36-year lifetime.

Roman was designed from the ground up around three of the biggest unsolved problems in astrophysics: dark energy, dark matter, and the prevalence of planets beyond our solar system.

Dark energy is the mysterious force that’s causing the expansion of the universe to accelerate. We know it exists because Hubble confirmed it, but we still don’t understand what it actually is. Roman will tackle this question by conducting massive sky surveys that map the distribution and motion of galaxies over billions of years of cosmic history, building the most detailed 3D maps of the universe ever assembled.

Dark matter is the invisible substance that makes up roughly 27% of the universe’s total mass-energy. It will be studied through a technique called gravitational lensing. Roman will measure how the gravity of dark matter bends the light from distant galaxies, revealing the otherwise invisible scaffolding that holds the cosmos together.

Then there are the exoplanets. Roman won’t just detect planets the way Kepler or TESS did, by watching for dips in starlight as a planet crosses in front of its host star. It will also use a technique called microlensing to find planets that don’t transit at all, including free-floating rogue worlds drifting through the galaxy untethered to any star. This approach is expected to uncover types of planets that no previous mission has been sensitive enough to detect.

Perhaps the most ambitious piece of technology aboard Roman is its Coronagraph Instrument. Built by NASA’s Jet Propulsion Laboratory, this system uses a combination of masks, prisms, detectors, and self-flexing deformable mirrors to block out the glare of a star so that planets orbiting around it can be photographed directly.

The coronagraph is officially classified as a technology demonstration rather than a primary science instrument, but if it works as designed, it will mean roughly a thousandfold improvement over any coronagraph ever flown in space. During its first 18 months of operation, the coronagraph will target Jupiter-sized planets and debris disks around nearby stars. If performance meets expectations, it could be opened up to the broader scientific community for additional observations.

More importantly, the coronagraph is a proving ground for the techniques that NASA’s proposed Habitable Worlds Observatory will need in order to succeed.

The telescope is named after Dr. Nancy Grace Roman, an astronomer born in Nashville, Tennessee, in 1925, who became the first woman to hold an executive position at NASA when she was appointed the agency’s first Chief of Astronomy in 1961. Known as the “Mother of Hubble” for her foundational role in getting the Hubble Space Telescope designed, approved, and funded by Congress, Roman spent decades fighting for space-based astronomy at a time when most ground-based astronomers were skeptical of the concept and women in science faced routine discouragement.

When Roman joined NASA in 1959, just six months after the agency was established, she was the sole person deciding which astronomy proposals went forward. She spent the next two decades building the case for a large space telescope, lobbying Congress, organizing scientists, and pushing through technical decisions, including the adoption of charge-coupled device (CCD) detectors that would define Hubble’s capabilities. Roman retired from NASA in 1979, eleven years before Hubble launched, but remained active as a consultant, educator, and advocate for women in science until her death on Christmas Day, 2018.

Roman will ride a SpaceX Falcon Heavy to the Sun-Earth L2 Lagrange point, roughly one million miles from Earth From that vantage point, shielded from the Sun’s heat and far from Earth’s interference, Roman will begin its five-year primary mission of surveying the sky in infrared light.

The Roman Space Telescope is part of a mission that’s likely to reshape our understanding of the universe in ways we can’t fully predict yet. When Hubble launched in 1990, nobody anticipated that it would help discover dark energy. Roman's designers have specific science goals in mind, but with an instrument this powerful surveying this much of the sky, the most exciting discoveries may well be the ones nobody saw coming.

We’ll be following the Roman Space Telescope’s journey to the launch pad and beyond right here at The Space Store. In the meantime, check out our collection of NASA merchandise and stay tuned for Roman-themed items as the launch approaches.

-Written by Matt Herr.