Most of the universe is still unknown. Even if you add up all the visible stars and galaxies, they account for less than 5% of the universe’s total composition. A next-generation space telescope designed to trace the rest will be sent to the launch pad at the end of this month.
The U.S. National Aeronautics and Space Administration (NASA) plans to launch its next-generation space telescope, “Nancy Grace Roman,” from Kennedy Space Center in Florida on the 30th. A SpaceX Falcon Heavy rocket will be used for the launch. After about three months of testing in orbit, it will begin full-scale observations. The total project cost is estimated at around $4 billion, or about 5.5 trillion won.
The telescope is named after Nancy Grace Roman, NASA’s first chief astronomer. She led the creation of the Hubble Space Telescope and became known as the “mother of Hubble.” The telescope bearing her name now follows in Hubble’s footsteps.
The Roman telescope has a 2.4-meter primary mirror and a 300-megapixel infrared camera. Its mirror size is the same as Hubble’s when it was launched in 1990. The primary mirror is a refurbished mirror originally built for a U.S. reconnaissance satellite and later transferred to NASA. This allowed NASA to reduce development costs while securing optical performance on the level of Hubble.
The difference in performance lies in the field of view. Roman’s field of view is more than 100 times wider than Hubble’s.
If Hubble was like peering into a room through a keyhole, Roman is like opening a window wide. It maintains the same resolution while surveying a much broader swath of sky at once. That is why surveys that would take Hubble decades can be completed in just a few years.
There is also a reason for using infrared light. Infrared can penetrate cosmic dust clouds and capture ancient light whose wavelength has been stretched as it traveled from great distances. That makes it ideal for finding early galaxies and faint celestial objects.
The telescope will be stationed about 1.5 million kilometers from Earth at a gravitational balance point. It is the same region where the James Webb Space Telescope is located, allowing stable observations free from Earth’s shadow and heat interference.
If the James Webb Space Telescope, launched in 2021, is a telescope that digs deeply into narrow regions, Roman is a surveyor that sweeps broadly across the sky. Roman will be able to find large numbers of interesting celestial objects, which James Webb could then follow up with detailed observations.
According to scientific estimates, the universe is made up of about 5% visible matter, 27% dark matter, and 68% dark energy. Dark energy is an unknown force that accelerates the expansion of the universe. Roman will also take on the task of measuring the distances of thousands of supernovae to reconstruct the history of cosmic expansion.
Galaxies rotate faster than can be explained by the gravity of visible matter alone. That suggests the existence of something invisible that exerts gravity. Scientists call it dark matter. Roman will map the distribution of dark matter by measuring how the shapes of hundreds of millions of galaxies are warped by gravity.
Exoplanets will be found through a “cosmic magnifying glass.” Roman will use the microlensing effect, in which the gravity of a foreground star momentarily brightens the light from a star behind it. If a planet is present, a subtle trace remains in the brightness curve. This method requires continuously monitoring hundreds of millions of stars near the galactic center, making Roman’s wide field of view especially suitable. It is expected to discover thousands of new planets, including ones as small as Earth.
NASA scientist Julie McEnery said, “Roman will have an impact across all fields of astronomy,” adding, “The unexpected discoveries that lie ahead are what make Roman so exciting.”
Japan has joined the Roman project. It contributed to the development of equipment used for observing exoplanet atmospheres, and a JAXA facility in Nagano Prefecture will serve as a ground station receiving observational data.
Rather than competing to build the full telescope, Japan secured a stake through instruments and ground facilities. Participating-country researchers gain a voice in planning observations and using the data. McEnery also said she hopes Japan’s contribution will broaden scientific research.
Korea has also followed a similar path. The Korea Astronomy and Space Science Institute participated in the development of NASA’s infrared space telescope SPHEREx and launched it together last year. Since the launch of the Korea AeroSpace Administration, expanding participation in large international projects has been identified as the next challenge. The lesson from past cases is that putting one’s name on components and instruments allows both technology and personnel to grow together.
Space telescope technology does not remain in the laboratory. Hubble’s image-processing technologies flowed into medical image interpretation, and its observational sensor technologies into the camera industry. Data-processing techniques developed for massive surveys also spread across many industries.
There are also opportunities even without direct hardware participation. Roman’s observational data are expected to be released immediately, with no exclusivity period. The data volume is projected to reach several terabytes per day, making them difficult to process without artificial intelligence tools. In other words, the side that analyzes the data first becomes the owner of the discovery. For universities and research institutes in Korea, this is a cost-free opportunity, so the key will be preparing data-analysis talent and computing resources.
The launch will be broadcast live on NASA’s internet stream. Once in orbit, the telescope will undergo focusing and instrument checks, and the first observation images will be released after the testing phase ends.
Hubble spent 36 years rewriting our understanding of the age of the universe and the rate of its expansion. Roman is also promising discoveries that could change the textbooks. When observations begin at the end of this year after the test run is complete, it will become clear how much of the universe’s remaining 95% can be unveiled.