NASA launched the Nancy Grace Roman Space Telescope on August 30, initiating a mission to investigate dark energy, dark matter, and millions of exoplanets. Weighing as much as a Tyrannosaurus rex and featuring a field of view 100 times larger than Hubble, the observatory will begin delivering data early next year.
The observatory successfully lifted off from Florida on August 30 and is spending three months traveling to a Sun-Earth Lagrange point a million miles away, where the gravity of the two bodies remains in equilibrium. Scientists and engineers spent some twenty years designing and building the spacecraft, which matches the size of a tour bus and weighs as much as a Tyrannosaurus rex.
Mapping the Dark Universe From a Million Miles Away
Once operational, the observatory will tackle two of the most elusive puzzles in modern astrophysics: dark matter and dark energy. The Roman Space Telescope traces its origins to the early 2000s, when cosmologists had known for a couple of decades that the matter we experience every day and observe with telescopes accounted for only a fraction of the universe’s matter, with huge amounts of so-called dark matter gluing the cosmos together. The late 1990s brought a second shocking space oddity — that the universe isn’t just expanding, but expanding faster and faster as time passes, driven by another incomprehensible phenomenon astrophysicists dubbed dark energy. Until now, understanding these two mysteries has been a steep challenge because both enigmas unfold on a huge scale, calling for observations of huge regions of the universe, according to Katarina Markovic, a cosmologist at NASA’s Jet Propulsion Laboratory in Pasadena, California. The telescope will map invisible matter by detecting tiny changes in the shapes of millions of galaxies caused by dark matter passing between these objects and the telescope, letting science map the invisible like window glass that has been warped by age.
Hunting Tens of Thousands of Exoplanets in the Milky Way
Beyond cosmic acceleration, a major share of the mission focuses on discovering alien worlds. Named after Nancy Grace Roman, NASA’s first chief of astronomy and a vital advocate for the Hubble Space Telescope, the observatory carries an advanced Coronagraph Instrument. This system utilizes a series of masks, baffles, stops, and detectors to identify and screen out blinding starlight, allowing researchers to image dim planets circling other stars.
One especially neat part of the coronagraph involves two flexible mirrors, powered by hundreds of tiny pistons, which shape the mirrors to serve as prisms to fit the exact wavelength of the light it’s trying to block, and the light it’s attempting to image. While previous missions have directly imaged a short list of mostly young, infrared-bright planets far from their stars, the new hardware will see closer planets, perhaps in their system’s habitable zone, examine planetary atmospheres via spectroscopy mode, and potentially detect whether an exoplanet has clouds or an atmosphere.
Surpassing Hubble and Webb With a Massive Field of View
The mission distinguishes itself through survey capacity. While observatories like Hubble and other NASA observatories see only a small fraction of the sky, the new telescope features a field of view 100 times larger than Hubble’s and can agilely pan across the sky to rapidly sweep the cosmos.
"Roman’s superpower is our surveys," methodically covering territory without specific targets, says astrophysicist Julie McEnery of NASA’s Goddard Space Flight Center (GSFC) in Greenbelt, Md.
Cosmologist Jason Rhodes of NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif. notes that "Anywhere you point Roman, somebody’s going to be able to say, ‘I discovered something,’" adding that "Roman is going to touch or affect nearly all areas of astrophysics."
"Roman is going to unlock huge corners of science by really turning that sharpness over vast areas of the sky," says astrophysicist Erik Rosolowsky of the University of Alberta in Edmonton, Canada, who is not formally affiliated with the Roman mission.
A Shakedown Period Before Early Operations
The observatory’s primary mirror, donated from the National Reconnaissance Office, is from a canceled spy program. The mission came in under budget and ahead of schedule. Following a shakedown period to make sure everything’s working OK, Roman won’t officially enter service until some time next year, with plans to start delivering a flood of cutting-edge astronomical data early next year and unlock mysteries about dark matter and dark energy within the mission’s first five years.
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