NASA's Swift Space Telescope Returns to Earth After More Than Two Decades in Orbit

The Swift space telescope, launched by NASA in 2004, completed 22 years of service in Earth orbit, exceeding initial expectations for a mission planned for only two years.

The equipment remained operational for such a long period that it even survived its designer, astrophysicist Neil Gehrels, who passed away in 2017. The following year, the observatory was renamed in his honor as the Neil Gehrels Swift Observatory.

Swift's operations were terminated by NASA on October 20. According to the latest forecast from the U.S. Space Force, the telescope, which weighs approximately 1.5 tons, is expected to re-enter the atmosphere this Wednesday (4) at 3:30 AM New York time, with an error margin of 11 hours.

During re-entry, most of the satellite will be pulverized due to air friction, reaching speeds of about 27,000 km/h, turning it into a fireball. However, some more robust components, such as mirror pieces and tungsten materials, may reach the ground intact.

The exact location of the fall is unknown. Since Swift orbits in a restricted band near the Equator, debris could reach the surface between latitudes 20.6° North and 20.6° South, an area encompassing parts of Brazil, from Amapá to Vitória (ES). However, the most probable outcome is that everything will end up in the ocean, with NASA calculating the chance of any person on the planet being hit at 1 in 2,100.

The reason Swift is falling is that, like most artificial satellites, it lacks a propulsion system to maintain its orbit. It was placed in orbit at an altitude of about 600 km, where the atmosphere is very thin, and it maintained its position thanks to a speed of almost 8 km per second, which allowed it to resist gravitational pull.

Over time, however, the satellite gradually loses speed and consequently altitude, a common process in low-Earth orbit satellites. In Swift's specific case, the acceleration of this loss was influenced by the Sun. In 2024, our star reached the peak of its activity cycle, which repeats every 11 years. Greater solar activity implies more energy released onto Earth, causing the upper atmospheric layers to heat up and swell, making the air occupy higher altitudes and forcing the satellite to collide with more molecules than expected.

NASA attempted intervention, investing $30 million in the American company Katalyst Space to develop a rescue device: a satellite equipped with robotic arms called LINK, intended to grab and propel Swift into a higher orbit. This satellite was launched in July but faced difficulties with orientation control and consumed excessive fuel while trying to stabilize, leading to the cancellation of the rescue in August.

While awaiting assistance, the team at the Pennsylvania State University, responsible for Swift's operation, had reduced most observations and adjusted the telescope to an aerodynamic configuration, minimizing air resistance. Upon receiving news of the rescue's infeasibility, scientists reactivated the instruments to utilize the final months, which ironically accelerated the fall, as changing targets required satellite movement and worsened the friction problem.

On October 20, at an altitude of 275 km, Swift entered safe mode, and controllers issued the final command to terminate the mission.

Swift leaves a notable legacy, with its data present in approximately 7,000 scientific articles, and currently, there is no ready replacement for its functions. Its importance lies in its ability to detect violent cosmic radiation, such as gamma rays, which are blocked by the Earth's atmosphere, making it essential for detectors to be in orbit. Furthermore, Swift could observe lower-energy wavelengths, such as X-rays, ultraviolet, and visible light.

For astronomers, this multispectral capability is crucial, just as a color photograph provides more detail than a black and white one. An observation across various wavelengths offers more information about a phenomenon than one restricted only to gamma rays. Another unique feature of Swift was its ability to continuously scan the sky and automatically maneuver to focus on interesting targets.

Swift represents one of the most durable observatories of its generation, marking popular memory in the 1990s and 2000s. Hubble, another famous telescope, faces a similar situation: without a propulsion system, it loses altitude annually and is expected to re-enter around 2033. NASA opened a consultation at the end of October to see if private companies could boost or guide it to a controlled descent, and the outcome of the Swift case may offer valuable lessons for this new endeavor.

The rescue operation for NASA's Observatório Neil Gehrels Swift space telescope, which had been in Earth orbit for twenty years, has failed. According to estimates, the spacecraft will re-enter the planet completely uncontrolled between Tuesday (the 3rd) and Wednesday (the 4th).

During its time in space, the satellite used three specialized scientific instruments to observe intense light signals in the universe: the Burst Alert Telescope (BAT), the X-ray Telescope (XRT), and the Ultraviolet and Optical Telescope (UVOT).

However, the orbital altitude has significantly decreased in recent weeks due to constant friction with rarefied gases. This has brought the observatory dangerously close to the Earth's surface, making remote control absolutely impossible for operators on the ground.

Technicians attempted to save the structure using a robotic mission sent by a partner company, but the plan fell through. The rescue spacecraft encountered serious problems with its stabilization system, began spinning uncontrollably, and expended too much fuel, preventing docking.

This incident halted all planned scientific activities. The exact landing site of the Swift's metallic remains is currently unknown. Darren McNait, a senior technical officer at LeoLabs, a company specializing in space traffic monitoring, told Space.com that 'most of it will evaporate and melt.'

According to experts, the number of old satellites and debris falling to Earth has increased significantly in recent years. Fortunately, the risk of any fragment causing serious damage to populated areas is considered very low, as the trajectory passes predominantly over oceanic regions far from continents. Major international agencies monitor outer space daily to avoid surprises.

Most of the telescope's main body is made of aluminum and lightweight materials that quickly melt in the intense heat generated by high speed. Only more durable metal parts and heavy lenses can withstand the high temperatures and reach the ground without completely evaporating during rapid passage through the Earth's atmosphere, challenging the initial predictions of responsible engineers.

These official data points have been closely monitored by responsible bodies in the US government's technology and space sectors, which guarantee full transparency regarding the real risks associated with the disposal operation.

The continuous increase in uncontrolled re-entries reflects the accelerated growth of recent space launches conducted by various private companies worldwide. Because of this, aerospace engineers are advocating for new satellites to be built from more suitable materials.

These components should be designed to completely disappear after their service life in near-Earth space, preventing persistent orbital pollution. Private companies and governments are discussing new regulations to curb the growth of space debris.

Outer space sustainability has become an urgent issue for ensuring safety for all in the coming years, requiring significant investment in clean technologies and safe decommissioning plans for every piece of equipment launched into space by space agencies. Constant monitoring helps protect lives and valuable property from unforeseen accidents caused by old debris completing its lifecycle, unpredictably entering the Earth's atmosphere in recent years.

The international scientific community continues to track the development of this historic re-entry, planning new, more effective methods to combat the growing traffic of obsolete satellites currently orbiting our blue planet during this period of technological expansion. Incidents like this underscore the urgent need for stricter regulations for the global space sector, ensuring that scientific progress goes hand-in-hand with environmental safety and the preservation of human life on land.

NASA has formally ended the mission of the Swift space telescope after a rescue attempt was unsuccessful. This observatory, which dedicated more than two decades to studying the Universe, is in the process of losing altitude and is expected to re-enter Earth's atmosphere in the coming weeks.

The rescue operation was conducted by Katalyst Space Technologies, a company based in Arizona, United States. This company developed the spacecraft named LINK with the purpose of reaching the telescope and elevating it to a higher orbit, enabling the continuation of its scientific investigations.

However, the initiative was not successful. Approximately three weeks after its launch, on July 3rd, the LINK spacecraft encountered problems with its propulsion system and the reaction wheels responsible for maintaining its orientation. These failures caused the spacecraft to spin at an unexpected speed, which made capturing and elevating Swift impossible.

Despite the setbacks, LINK managed to approach the observatory and take photographs of it. The separation between the two spacecraft varied between 12 and 15 kilometers, which proved insufficient to complete the planned operation.

Swift was losing altitude due to atmospheric drag and does not have adequate thrusters to neutralize this effect. In September 2025, NASA awarded Katalyst a contract worth US$ 30 million (equivalent to about R$ 162 million) to attempt to save the observatory.

The adopted strategy involved a spacecraft comparable in size to a refrigerator, equipped with three robotic arms. The concept was for LINK to reach Swift, capture it, and guide it to a higher orbit. This mission was pioneering, as no private spacecraft had managed to capture and elevate a satellite that was not designed to receive such maintenance. Speed was also crucial, given that Swift continued to lose altitude while the operation preparation proceeded.

Although the attempt failed to extend the telescope's lifespan, NASA considered the project valuable for fostering the development of robotic maintenance technologies in space and for testing the capacity to execute operations of this magnitude in short periods.

Swift was officially named the Neil Gehrels Swift Observatory in 2018, in memory of its first principal investigator, who passed away the previous year. With the end of the mission, the observatory will return to Earth's atmosphere in the coming weeks, but the collected data will remain accessible for future scientific research.