Earlier this year, NASA announced that it will launch a new space telescope, the Nancy Grace Roman Space Telescope, into orbit. Roman could mark a major milestone in astronomy. To gather data on space, humans have been using different methods to learn about our planet, the solar system, and space. One of the most useful tools has been, of course, telescopes. Developed during the 1600s, telescopes helped astronomers and scientists observe stars and planets in the universe. Humans later built space telescopes, which are sent into space to observe celestial bodies. Earth’s atmosphere distorts light and blocks some wavelengths. Space telescopes avoid these effects, capturing clearer images across a wider range of wavelengths. first successful orbiting astronomical observatory was the Orbiting Astronomical Observatory 2 (OAO-2), launched in 1968 into Low Earth Orbit. It sent data to scientists on Earth for 4 years and helped to provide the first observations of astronomical objects in ultraviolet light. Currently, there are tens of space telescopes in orbit, and each of them is specialized for different missions. This article explores major space telescopes and the current development of space telescopes.
The most famous space telescope is the Hubble Space Telescope. The Hubble Space Telescope is a large telescope that is orbiting Earth. Hubble’s discoveries have transformed our understanding of the universe. It was launched in 1990 into low Earth Orbit with the objective of “understanding the universe.” Since Hubble’s launch, it has contributed to every major area of astronomy as it has observed different bodies, such as galaxies, stars, black holes, and exoplanets. The most surprising fact is that it is still active nowadays, 36 years after its launch. This is possible due to its advantage of being able to be repaired in space. Since its position is very close to Earth, astronauts on Space Shuttle missions can visit and repair the components. One of the most significant incidents was soon after its operation, when the scientists found out that its primary mirror had a tiny error that caused blurry images. Rather than losing an extremely expensive spacecraft, NASA decided to fix it in orbit, as they sent astronauts to install corrective optics. Its accomplishment is that it discovered more than 3,000 unknown galaxies when it pointed at a seemingly empty space, discovering that space is not empty, but full of stars and galaxies. After all, it is considered one of the biggest accomplishments in astronomy, as NASA describes Hubble as an instrument that has “changed humanity's understanding of the universe.”
Next is the largest and most complex astronomical observatory sent into space, the James Webb Space Telescope. It was launched in 2021 into the Second Lagrange point, or L2, and is orbiting the Sun 1.5 million kilometers from Earth. Unlike Hubble, which mainly observes visible and ultraviolet light, Webb specializes in observing infrared light. This trait allows it to see through the clouds and dust, observe the stars and planets that are forming, study extremely distant galaxies, and detect stretched light by the expansion of the universe. One of its recognizable features is its giant primary mirror, which consists of 18 hexagonal segments that work together to form a single mirror measuring 6.6 meters across. Webb’s larger mirror collects more light, allowing it to detect fainter objects. Webb’s specific goals with infrared observation are to study the early universe by observing the earliest galaxies after the Big Bang; to study galaxy evolution by observing how small galaxies develop into enormous galaxies; and to study the formation of stars and planets by seeing through the dust, where it can examine stellar nurseries where new stars and planetary systems are forming. It is also revolutionary, as it made the first direct measurement of an exoplanet atmosphere. It can observe different wavelengths to determine which molecules are present in an exoplanet’s atmosphere. This technology was innovative to scientists, as its much greater infrared sensitivity and wavelength coverage allowed scientists to detect more molecules and obtain much more detailed atmospheric measurements. Thus, Webb is one of the greatest feats in expanding astronomical observation.
The Nancy Grace Roman Space Telescope adds another capability: observing vast areas of the sky with sharp detail. Its wide-field instrument is designed to capture a region at least 100 times larger than Hubble’s infrared field of view, with comparable image sharpness. If Hubble takes a detailed photograph of a small region, Roman can capture an enormous panorama. This combination will allow astronomers to survey large populations of stars and galaxies much more efficiently. One of Roman’s main goals is to investigate dark energy, the cause of the universe’s accelerating expansion. Its surveys will also help map dark matter and discover exoplanets. In addition, its coronagraph instrument will demonstrate technology that blocks a star’s glare, allowing faint planets and disks around it to be imaged directly. These capabilities serve different purposes: broad surveys will reveal large-scale patterns, while the coronagraph will test tools for studying individual planetary systems.
Together, Hubble, Webb, and Roman show how complementary instruments can expand astronomical discovery. Hubble provides detailed observations across ultraviolet, visible, and near-infrared wavelengths; Webb investigates faint infrared sources, including early galaxies and forming planetary systems; and Roman will bring a panoramic perspective to the universe. Its repeated surveys will help astronomers identify changing objects and discover targets for closer study. By combining detailed views with a broader picture of the sky, these telescopes can help us understand both individual worlds and the universe they belong to.
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