New Delhi: NASA’s Neil Gehrels Swift Observatory has ended its scientific operations after nearly two decades of studying some of the universe’s most energetic phenomena. The spacecraft is expected to re-enter Earth’s atmosphere in the coming weeks. The observatory, which transformed the study of gamma-ray bursts and other high-energy cosmic events, was forced to shut down after increased atmospheric drag caused it to lose altitude rapidly. Swift entered safe mode on October 20 after descending to an altitude of around 275 kilometres, leaving it unable to compensate for the effects of atmospheric drag.
Following the development, the operations team at Pennsylvania State University in University Park sent a command that effectively brought Swift’s science mission to an end and prepared the spacecraft for its eventual atmospheric re-entry. Like other satellites in low Earth orbit, Swift experiences atmospheric drag as it travels through the upper layers of Earth’s atmosphere. Recent increases in solar activity intensified this effect, accelerating the spacecraft’s descent.
A high-risk servicing mission intended to raise the observatory’s orbit ended in August without an attempt to boost its altitude. Swift had temporarily suspended scientific observations to reduce atmospheric drag and extend its time in orbit while the team pursued the planned boost mission. After the mission concluded, the spacecraft resumed observations and collected data on hundreds of targets.
These included remnants of stellar explosions, active supermassive black holes in distant galaxies and comets within the solar system. However, resuming observations increased atmospheric drag, accelerating the spacecraft’s descent once again. Launched in November 2004, Swift was designed to detect gamma-ray bursts — brief but extraordinarily powerful explosions associated with catastrophic cosmic events, including the collapse of massive stars and the mergers of compact stellar objects.
Its ability to rapidly detect these bursts and coordinate observations across multiple wavelengths helped scientists investigate their origins and understand the extreme environments in which they occur. The observatory also contributed significantly to research on black holes, supernovae, stellar flares and other short-lived astronomical phenomena. Its observations enabled astronomers to study cosmic events ranging from nearby stars to distant galaxies billions of light-years away.
Although Swift’s scientific operations have ended, its extensive archive is expected to remain a valuable resource for researchers, supporting future studies and discoveries. As the spacecraft descends towards Earth, its mission will eventually conclude with atmospheric re-entry. Most of its components are expected to be destroyed by intense heat during the process, although the fate of individual components will depend on the conditions of re-entry. Swift’s scientific legacy, however, will continue through the discoveries it enabled and the vast collection of astronomical data it leaves behind.
