scouring the cosmos

Nancy Grace Roman Space Telescope: How NASA will build on Hubble's legacy

Scheduled for launch by 2025, the new observatory is designed to unravel the mysteries of dark matter.

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In the last century, we have observed the infinite universe using massive lenses suspended in space. Together, these telescopes — Hubble, Chandra, the Transiting Exoplanet Survey Satellite, and others — have shed light on our place in the cosmos beyond the wildest imaginations of the ancient astronomers who inspired their missions.

The more our modern technology progresses, the better we can see millions of light years away and discover these hidden mysteries. But there is perhaps no mystery so great as that of dark matter. Thought to make up some 25 percent of the universe' total mass, dark matter has eluded our gaze. Soon, however, we may have answers.

By 2025, NASA will launch a telescope designed to unravel the mystery behind dark matter. The telescope, a continuation of the Hubble Space Telescope's legacy, is named for one of the scientists who inspired that telescope, Nancy Grace Roman.

Nancy Grace Roman (1925-2018), NASA's first chief astronomer, is known as the 'Mother of Hubble.'


But this new telescope will have another, equally crucial, mission to accomplish, too: It will be the most advanced effort yet in trying to find worlds that resemble the planets in our Solar System, as well as unravel the mystery behind dark energy.

NASA's Nancy Grace Roman Space Telescope will succeed the Hubble in terms of the sheer size of its lens on the universe — offering a panoramic field view 100 times larger than that of the Hubble.

What is the Nancy Grace Roman Space Telescope?

The Nancy Grace Roman Space Telescope is a continuation of the work of the Hubble Space Telescope. It will survey 100 million stars and aims to discover 2,500 new exoplanets. Previous missions such as NASA's Kepler and Transiting Exoplanet Survey Satellite have found more than 4,000 exoplanets. But they were mostly large planets, orbiting around dim stars.

The Roman Space Telescope, on the other hand, will search for Earth-like, smaller, rocky planets which orbit around bright stars in the hopes of finding a habitable world similar to ours.

The telescope's camera is just as sensitive as the one on the Hubble Space Telescope, but with a much larger field of view. That means that Roman will be able to capture an area of the sky that's 100 times larger than the images captured by Hubble, albeit with the same sharpness.

Here's a video explaining how our view on the cosmos will change:

Roman will search for exoplanets using a technique known as microlensing. The gravitational fields of large objects such as stars will actually bend and magnify the light coming from an object behind them, which produces a halo in space.

When a star passes in front of another star, it will bend the star's light, making it bright like a lens. If that star has an exoplanet orbiting around it, the planet's gravitational field will also have the same effect, making it even brighter.

How will the Roman Space Telescope investigate dark matter?

Aside from finding exoplanets, the Roman Space Telescope will also study one of the biggest mysteries of the universe: Dark matter and dark energy.

Dark matter and dark energy are believed to make up the bulk of the universe, and may be responsible for the universe's expansion. It is an unknown form of energy that fills up space, and yet has never been directly observed.

Dark matter alone is though to make up around 27 percent of the universe, while normal matter, the stuff that we are able to observe, is believed to only be about five percent.

Rather than trying to observe dark energy, the Roman Space Telescope will study how the distribution of galaxies and dark matter has changed over the billions of years of the universe's existence. The telescope will also study the death of stars that took place billions of years ago by using ancient supernovae as a marker of cosmic time.

Since dark energy may be responsible for the universe's expansion, observing how the cosmos has evolved over time will help scientist better understand this strange force at work.

The Roman Space Telescope's surface is figured to a level hundreds of times finer than a typical household mirror.

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When will the Nancy Grace Roman Space Telescope launch?

The Roman Space Telescope will launch in the year 2025, according to NASA.

It will have a primary mission lifetime of five years, which may potentially be extended for an additional five years.

Meanwhile, NASA's Hubble Space Telescope has been in operation for 30 years and is due for a long-awaited retirement. It was initially meant to go offline this year, but the date was pushed to the year 2025.

Hubble will be not only be followed by the Roman Space Telescope, but by the James Webb Telescope as well.

Who is Nancy Grace Roman?

The Roman Space Telescope is named after Nancy Grace Roman, NASA's first chief astronomer.

Although it was initially known as the Wide Field Infrared Space Telescope (WFIRST), NASA renamed it as the Nancy Grace Roman Space Telescope in 2020 to commemorate the legacy of Roman who died in 2018.

Roman paved the way for women in the field of astronomy. She was the first Chief of Astronomy in the Office of Space Science at NASA Headquarters and the first woman to hold an executive position at NASA.

Roman is often referred to as the 'Mother of Hubble' as she set up a committee of astronomers and engineers in the 1960s for the development of space telescopes, which later lead to the birth of the Hubble Space Telescope.

Roman Space Telescope fast stats:

  • The telescope will hover about 930,000 miles above the Earth in the direction opposite the Sun.
  • Roman’s primary mirror is 7.9 feet across.
  • However, the mirror only weighs 410 pounds thanks to major advancements in technology.
  • The telescope carries a 300-megapixel infrared camera known as the Wide Field Instrument.
  • Each of its images will capture a patch of the sky bigger than the apparent size of a full Moon.
  • Over the first five years of observations, Roman will image over 50 times as much sky as Hubble covered in its first 30 years.

Editor’s note: This article was updated on July 31, 2023, to reflect the correct amount of mass that dark matter makes up of the universe.

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