Thirty-five years have passed since the Hubble Space Telescope was launched into orbit around Earth, and like a fine wine, it has only improved with age. As of April 2025, contrary to all expectations, Hubble is not only surviving but is in excellent technical condition, more scientifically active than ever, and continues to provide the world with unprecedented observations.
The Hubble Telescope, a joint project of NASA and the European Space Agency, was launched into space in 1990 with a clear goal: To free astronomy from the confines of Earth's atmosphere and capture the universe with a sharp, infrared-sensitive eye that had never been available before. Indeed, since its entry into orbit, Hubble has become the most influential astronomical research instrument of the 20th century and a cultural brand in its own right.
Over the years, Hubble has been at the center of some of the most significant discoveries in modern astronomy. It proved that every large galaxy contains a massive black hole at its core, documented in real-time the expansion of the remains of Supernova 1987A, discovered dark energy accelerating the expansion of the universe, and captured the deepest photograph ever taken of the ancient universe – a journey 13 billion years back in time. It was even a pioneer in the study of the atmospheres of exoplanets, providing insights into weather changes on large gas giants like Jupiter and Neptune.
Hubble's journey has not always been smooth. Shortly after its launch, it was discovered that one of its main mirrors had been ground incorrectly, impairing the quality of its imaging. In 1993, in a daring mission, astronauts aboard the Space Shuttle Endeavour installed a corrective optical system, restoring its vision – and with it, the trust of the scientific community. Due to its space-based maintenance, Hubble underwent four additional servicing missions, the last of which took place in 2009, during which instruments were replaced, more advanced ones installed, and critical systems refurbished.
Today, at 35, the telescope is operating in exceptional condition. Even after the number of its gyroscopes (used for directional precision) decreased to three – and one of them ceased functioning – NASA’s ground crew succeeded in operating Hubble in a new mode, relying on only a single gyroscope. This creative technical solution has allowed the telescope to continue functioning, despite earlier estimates predicting the end of its life at an earlier stage.
One of Hubble's main research tools today is the Cosmic Spectrograph (COS), which measures ultraviolet light – a range of observation that Earth's atmosphere completely blocks. It is the only tool of its kind in the world today, allowing the detection of processes such as star formation, large-scale cosmic structure, and the composition of the atmospheres of stars and planets.
In addition to its unique capabilities, Hubble maintains its relevance thanks to collaborations with other observatories – from the Spitzer Space Telescope and the Chandra X-ray Observatory in the past to the ALMA radio array in Chile and the groundbreaking James Webb Space Telescope today.
While the JWST excels at studying ancient galaxies in infrared light, Hubble focuses on closer galaxies, observing visible and ultraviolet light. The combination of the two allows for the creation of a complete cosmic history: Understanding the formation processes of galaxies, stars, planets, and life itself – across the entire timeline of the universe.
One of Hubble's most significant advantages is the length of time it has been active. The ability to observe objects over decades allows for unprecedented monitoring of slow processes: Changes in the atmospheres of planets, supernova explosions, the inflation of changing black holes, and strange bursts of light that appear and disappear – all of which are documented in sequence thanks to the telescope's consistency.
Despite everything, Hubble does have an expiration date. Without an intentional orbit adjustment, atmospheric drag will eventually cause it to sink and burn up in the atmosphere by the 2030s. The true successor to Hubble – a large optical-ultraviolet telescope twice the size – is not expected to launch before the 2040s. Proposals to save Hubble by sending a robotic spacecraft to push it into a higher orbit are already being considered, but for now, Hubble continues to operate as if no time has passed.
The elderly telescope that survived malfunctions, space disasters, budget cuts, and technological competition proves that even at an advanced age, it is possible to change the way we look at the universe. And it has been doing so, in an awe-inspiring way, for 35 years.
