The GAPS (General AntiParticle Spectrometer) experiment has successfully launched from Antarctica, beginning its mission to study antimatter in cosmic rays. The launch took place from NASA’s McMurdo Station on Monday, December 15 at 17:37 Italian time (05:37 NZDT on Tuesday, December 16), carried aloft by a large stratospheric balloon to an altitude of approximately 37 kilometers. Initial system checks confirmed that all equipment is functioning normally, and the experiment is now collecting its first scientific data.
The GAPS collaboration, supported by NASA, brings together research institutions from the United States, Japan, and Italy. The Italian contribution - backed by the Italian Space Agency (ASI) - includes researchers from the National Institute for Nuclear Physics (INFN) and the Universities of Firenze, Pavia, Bergamo, Napoli, Torino, Roma Tor Vergata and Trieste.
The launch was conducted as part of the activities at the Long Duration Balloon (LDB) base of NASA’s Columbia Scientific Balloon Facility (CSBF) in Antarctica—a unique facility located around 78 degrees south latitude. The special atmospheric conditions there allow stratospheric balloons to complete long-duration flights, sometimes lasting several weeks, following circular paths around the South Pole. This enables scientists to gather large amounts of data in an ideal environment for the study of cosmic rays.
The scientific goal of GAPS is ambitious: to study the extremely rare component of antimatter in cosmic rays—energetic particles originating from space—with particular attention to low-energy antinuclei such as antiprotons, antideuterons, and antihelium. Detecting these signals could provide fundamental clues about the nature of dark matter, one of the major unsolved mysteries in modern physics.
To achieve this, GAPS uses an innovative technique. When an antimatter particle enters the detector, it is captured by atoms in the material and forms an “exotic” atom, in which the negatively charged antimatter particle orbits a positively charged nucleus. The subsequent annihilation of the antinucleus and the decay of the exotic atom emit characteristic signals. By analyzing these signals, scientists can precisely identify the type of antiparticle observed.
A key contribution to the development of the experiment comes from Italy. The Italian component of the collaboration designed and built the tracker—the system that measures the direction of incoming cosmic rays—based on silicon sensors and a sophisticated readout and power electronics system, capable of detecting very rare events amid the enormous flux of cosmic particles.
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23 December 2025
