The Nancy Grace Roman Space Telescope is one of those NASA projects that may suffer from budget cuts. However, this instrument should be the next step in the development of infrared astronomy, which is now one of the most important fields in stellar science, and for good reason.
Plans to reduce NASA’s budget
In mid-April 2025, it became known that in its budget proposal for 2026, the Donald Trump administration proposes to cut NASA’s spending drastically. In particular, the scientific division of this organization, which currently has a budget of about $25 billion, should suffer the most.
Funding for heliophysical missions may be cut in half; 2/3 of astrophysicists involved in deep space research may also be laid off. Out of all the space telescopes, only JWST and Hubble are agreed to be funded.
The news of the possible cancellation of the launch of the Nancy Grace Roman Space Telescope has caused the most noise in the scientific community. The telescope has been assembled for many years and is now nearing completion. However, it may never go into space.
The Nancy Grace Roman Space Telescope, or Roman Space Telescope, as it is also called, is the next step in the development of infrared astronomy. It is hard to say why the new US administration decided that it was not needed.
Perhaps they saw that there are already several infrared telescopes in orbit, so scientists can make do with them. However, there is a good reason why there are so many astronomical instruments operating in this range, but scientists need even more of them. To understand this, it is worthwhile to understand what is special about infrared wavelengths.
Infrared radiation
Until the nineteenth century, scientists had never heard of any infrared radiation. But in 1800, the English astronomer William Herschel began to study the Sun in depth and discovered that his instruments were getting very hot. He began to look for ways to reduce this effect and, to this end, decided to find out which wavelengths of visible light (also known as colors) have a stronger effect on the telescope.
Imagine Herschel’s surprise when he discovered that the maximum energy from the Sun comes in waves that are beyond the red spectrum and invisible to the human eye. However, scientists quickly figured out this phenomenon because they realized that infrared rays are emitted by any heated body. We are familiar with this phenomenon from the use of a thermal imager. It forms images in the dark thanks to this effect.
Even Herschel himself could have guessed that infrared rays could be used to obtain images. But it was of no practical importance. There was no way to make it visible to the human eye. To be more precise, a couple of decades later, a potentially suitable method emerged – photography.
At that time, however, images were captured not on a photocell matrix but on glass plates or film coated with certain substances. They produced images in black and white, but were sensitive mainly to blue and green colors. Even a clear image of something in red was a problem back then.
Infrared radiation detectors appeared only at the beginning of the 20th century. That is when infrared photography began to be used on Earth. But astronomers were not in a hurry to use it. The fact is that although near-infrared light was generally delayed by our planet’s atmosphere even less than visible light, several absorption peaks at longer wavelengths allowed us to observe stars only through separate “windows”. So scientists simply did not know why they needed to build telescopes that would operate at these frequencies.
The beginning of infrared astronomy
The situation changed in the 1950s and 1960s. At that time, radio astronomy achieved its first successes. And radio waves are exactly what is even further away than infrared light. So if they helped to see a bunch of objects that remained invisible in visible light, then perhaps it is worth looking for something in the near-infrared range.
It should be noted that infrared light is a rather broad concept. It is divided into three separate sub-bands: near (700 to 1400 nm), medium (1400-30,000 nm), and far (30,000-100,0000 nm). It is the near-infrared range that is usually used, which can be perceived by the same photocells as visible light. It is mainly used for both earthly needs and astronomy. For the middle and far-infrared ranges, the sensors must be immersed in a cooler to keep the temperature as low as possible.
The first experiments with infrared telescopes began in the 1960s, and it quickly became apparent that to work effectively, these instruments needed to be taken into the upper atmosphere, and ideally beyond it. One of the first projects was NASA’s Galileo flying observatory, which operated aboard a specially equipped Convair 990 aircraft from 1965-1973. It was primarily experimental and was used to observe Solar System objects, such as the Ikeya–Seki comet and Jupiter’s moons. Despite the limitations of the platform, these flights convincingly demonstrated that infrared telescopes will have a great future, once they are taken outside the atmosphere.
The main advantage of an infrared telescope is that it is a thermal imager. Any heated object emits energy even when it does not glow in the visible range. This means that it can potentially search for even very cold objects, such as brown dwarfs and interstellar gas clouds.
In addition, in the second half of the 20th century, one of the most important areas in sky science was the study of galaxies, quasars, and other objects outside the Milky Way. The light from these objects undergoes a strong red shift, so they can be seen well only in the infrared.
Another important advantage of infrared radiation is its ability to penetrate dense media much better than visible light. That is why in the infrared range, you can observe objects hidden behind dense clouds of dust and gas that otherwise remain invisible. This effect became especially pronounced in the 21st century, when astronomers began to explore distant galaxies.
Almost invisible matter scattered in intergalactic space can reduce the brightness of their visible light by almost half. In contrast, in the infrared range, these objects become much more contrasting. That is why modern science cannot do without infrared telescopes in studying the earliest stages of the Universe.
Infrared space telescopes
The fact that virtually the same CCDs are suitable for infrared radiation as for visible light made it easy enough to modify many of the largest ground-based telescopes, so they now operate in both bands.
However, the best results were still demonstrated by those instruments that were able to be raised above the tops of the highest mountains. Galileo’s work was continued by the Kuiper Airborne Observatory, which operated from 1974-1995. It made several important discoveries, including the discovery of Uranus’ rings in 1977 and Pluto’s atmosphere in 1988.
In 2010-2022, NASA, in cooperation with the German Aerospace Center, implemented another ambitious project, the SOFIA airborne observatory. It was an airplane equipped with an infrared telescope with a 2.5-meter diameter mirror that flew to an altitude of over 12 km. This approach made it possible to make several significant discoveries, including the discovery of water on some asteroids and its traces in the Moon’s temperate latitudes.
The first infrared space telescope was called IRAS. It was owned by NASA and operated in Earth orbit for 10 months in 1983. It was mainly used to observe comets and test the concept. The results of its work were excellent, but it became obvious that to fully study the Universe, a much more powerful device needed to be created – and this would take years.
In 1995, the Infrared Space Observatory (ISO) was launched into orbit. It was built by the European Space Agency with the help of the Japanese and Americans. It had 1000 times more sensitivity than IRAS and 100 times better angular resolution. ISO operated for three years and during this time was able to observe several tens of thousands of objects.
ISO has made many discoveries. It has studied protoplanetary disks and found planets in their early stages of formation; it has learned that planets can form around old stars and found water in molecular clouds near the center of the Galaxy. But most importantly, this spacecraft has seen a huge amount of gas and dust in intergalactic space, showing that future missions specializing in the study of extragalactic objects should also go beyond the visible spectrum.
The era of infrared space telescopes has arrived. In 1996, the U.S. military launched the Midcourse Space Experiment, which mapped the galactic plane. In 2006-2011, Japan’s AKARI operated in orbit and discovered supernova remnants in the Large and Small Magellanic Clouds.
However, the real breakthrough was the Spitzer Space Telescope, which was launched in 2003 and continued to operate until 2020. It has become the embodiment of what NASA specialists have wanted since the days of IRAS: a full-fledged infrared telescope in space.
Like most high-precision infrared instruments, Spitzer required deep cooling to operate as efficiently as possible. Once the coolant reserves were exhausted, the telescope’s sensitivity was significantly reduced. To extend the life of the active mission, the engineers applied several innovative design solutions, many of which have since become the standard for other infrared space observatories.
First, to protect it from the Sun’s rays, the spacecraft was protected by a special shield. Secondly, since the Earth also heats the spacecraft, it was put into a very tricky orbit. It is heliocentric, but the speed of the spacecraft is so little different from the speed with which the Earth itself moves around the Sun that it is close to it all the time.
Spitzer took pictures in false colors, but they were still impressive. Supernova remnants, protostellar objects that were just emerging in their stellar cradles, distant galaxies – the details of the structure of these objects were hidden in the dark, but infrared rays allowed us to see them in all their glory. It was also Spitzer that became the first telescope to see an exoplanet directly.
No less successful than Spitzer was the Herschel space telescope, which operated in space from 2009 to 2013. It still holds the record among space telescopes for the size of the main mirror, provided it is a single piece. In this space observatory, its diameter was 3.5 meters. The James Webb Space Telescope has a larger mirror – 6.5 meters – but it consists of separate segments.
The WISE mission
An infrared space telescope is a thermal imager in orbit. It does a good job of looking closely at one thing, and it does a good job of accurately determining the motion parameters of many objects. But when it comes to simply finding something that is well hidden from us, it is simply unrivaled.
However, this task requires a special type of telescope. It is not only important to have a large magnification or high angular resolution, but the width of the field of view is equally critical. It is this width that allows the instrument to quickly cover large areas of the sky to detect the faintest signals from the depths of space in time.
The Wide-field Infrared Survey Explorer (WISE) telescope, launched in 2009, is just such an example. It does not impress with its size or loud statements about revealing the deepest secrets of the Universe, but its results speak for themselves and perfectly illustrate why we need Roman.
In the list of star systems closest to the Sun, the third and fourth lines are occupied by objects discovered by WISE. Before that, it was updated a century ago. And the fact that these are brown dwarfs, i.e., sub-stellar objects, does not diminish the importance of this telescope. Because this small telescope has discovered dozens of such objects, but the rest are located farther from the Earth. The coldest class of these objects, called Y, was discovered by this telescope.
It is good to know what is going on with a quasar that shines at us from a distance of billions of light-years. But it is equally important to know what kind of objects are hiding from us right outside the Solar System. Could there be a ninth planet the size of Jupiter lurking out there? Or a planet the size of Neptune? Or a wandering brown dwarf?
The best answer to these questions to date also belongs to the WISE telescope. It has not found anything like it near the Sun, and thus has set the boundaries for the possibility of the existence of objects of different masses on the outskirts of the Solar System.
In addition, he discovered a lot within its borders. In particular, it discovered 365 near-Earth objects and 34 comets. Its mission ended in July 2024, and on November 1, it de-orbited and burned up in the Earth’s atmosphere.
So, why is the Roman Space Telescope needed?
There are currently three infrared telescopes operating in space. James Webb is the main astronomical instrument of our time. Its operating hours are scheduled months in advance, and discoveries based on its data are continuously being made.
The European mission Euclid has been operating since 2023. It mainly surveys the depths of space beyond the Milky Way. Recently, astronomers working with this telescope presented the first release of data containing 26 million galaxies. The main task of the device is to map as many star systems in the Universe as possible to understand where dark matter and dark energy are hidden in the Universe based on their distribution.
The third infrared space periscope is SPHEREx, launched just a few months ago. It has two main missions: to complement the Euclid survey by independently measuring the redshift of 450 million galaxies and to study what is happening in protoplanetary disks.
The idea of creating a wide-angle survey instrument similar to WISE, but bigger and better, has been discussed since early 2010. Eventually, it turned into the Nancy Grace Roman Space Telescope. It is intended to perform the widest possible range of tasks, from the search for dark matter to the detection of orphan planets. Its main task is to detect something that is not so far away from us, but due to various circumstances remains invisible even though it consists of quite ordinary matter.
The Nancy Grace Roman Space Telescope has gone through a lot of hard times over the past decade and a half, but it is impossible to say that it is a project that will never be implemented. The astronomical instrument itself and the space platform for it have already been manufactured and tested. The process of connecting them has been underway since 2025. After it is completed, all that remains is to test them together once again and then prepare them for launch.
Experts say this could happen as early as the fall of 2026, much sooner than previously planned. However, if NASA’s funding is indeed cut, it risks remaining on Earth.
