NASA's new Nancy Grace Roman Space Telescope is about to launch. Here's why it's so cool.

It's been more than 36 years since NASA sent its Hubble Space Telescope into low-Earth orbit, and nearly five years since the agency's James Webb Space Telescope started to circle the sun. Now a new, even more advanced hunk of astronomical hardware is set to follow its two pioneering predecessors into the cosmos: the Nancy Grace Roman Space Telescope.

After more than a decade in development, the Roman Space Telescope will launch at 7:20 a.m. on Aug. 30 from NASA's Kennedy Space Center in Florida — eight months ahead of schedule. Its mission? To study how the universe began, what it's made of and how it has evolved over time — while (hopefully) helping scientists solve some of modern astronomy's biggest mysteries in the process.

NASA will preview that mission at a virtual news conference today at 2 p.m. ET.

"We're going to find one-in-a-million things over and over and over again," Jeremy Perkins, a Roman Telescope scientist at NASA's Goddard Space Flight Center, recently predicted.  

What kinds of things? Habitable planets in our own galaxy, perhaps. And dark energy. And primordial black holes. 

To understand why the Roman Space Telescope matters, you first have to understand how it's different. Hubble mainly picks up visible light; Webb sees deep into the infrared part of the spectrum. Since light takes an unfathomably long time to travel from one end of the universe to the other, both space telescopes can peer far into the "past" — nearly back to the Big Bang, more than 13 billion years ago. But Webb — which also orbits in a quieter, darker part of space than Hubble, with less visual noise to block out — can capture distant celestial bodies in much greater detail. 

In some ways, the new, 42-foot-long Roman Space Telescope resembles Webb. It too can see infrared light, and it will join its slightly older cousin at the second Lagrange point — a sweet spot in our tug-of-war with the sun, nearly 1 million miles from Earth. But Roman's mirror — the part of the camera that collects light, like a bucket in a rain shower — is Hubble-sized (7.9 feet) rather than Webb-sized (21 feet). So Roman's images of the universe will be less detailed as a result.

What those images lack in relative resolution, however, they will more than make up for in sheer scope. With 18 sensors, Roman's 300-megapixel camera is what's known as a wide-field instrument — a panoramic technology rarely deployed in space until now. Roman's field of vision is 100 times larger than Hubble's, meaning it can survey the sky 1,000 times faster. Over the next five years, NASA expects Roman to cover 50 times as much interstellar territory as Hubble covered over three decades. By the end of its life, Roman will have measured the light from a billion galaxies. 

Why is such a wide field of vision important? Because the more sky you can survey, quickly and efficiently, the more "one in a million" leads you can generate — leads that Webb (and even Hubble) can then follow up on. 

According to NASA, the Roman Space Telescope will yield deep 3D images enormous enough to help astronomers probe whether an enigmatic, theoretical pressure called "dark energy" is actually making the universe expand faster over time. It will observe how clumps of dark matter warp the appearance of distant galaxies, potentially altering our understanding of the architecture of the universe itself. And it will sharpen our search for exoplanets by using a tool called a coronagraph to capture the first direct images of mature worlds similar to some of the planets in our outer solar system.

Fittingly, the Roman Space Telescope is named for Nancy Grace Roman — a trailblazing astronomer who classified different types of stars, measured how they moved and served as NASA's chief of astronomy in the 1960s and '70s. Known as the "Mother of Hubble," Roman was the agency's first woman executive. She died in 2018 at the age of 93.

In 2011, Roman recalled asking her high school guidance counselor if she could take second-year algebra instead of Latin. "She looked down her nose at me and sneered, 'What kind of lady would take mathematics instead of Latin?'" Roman told Voice of America. "That was the sort of reception I got most of the way."