Utilizing the Ultraviolet Spectroscopy (UVS) instrument onboard NASA’s Europa Clipper spacecraft, scientists have made significant observations of 3I/ATLAS. This interstellar object is the third and only confirmed of its kind to have been detected entering our solar system from beyond it. While many telescopes on Earth and Mars struggled to track such interstellar visitors due to their proximity to the Sun, Europa Clipper was able to gather data from a distinct position as it advanced towards Jupiter.
This composite image of interstellar comet 3I/ATLAS was captured on November 6, 2025, by the UVS instrument aboard NASA’s Europa Clipper spacecraft from a distance of around 164 million kilometers (103 million miles). Image Credit: NASA/JPL-Caltech/SwRI.
Scheduled to launch in 2024 and reach the Jupiter system by 2030, Europa Clipper will orbit Jupiter and conduct 49 flybys of its icy moon, Europa.
The UVS instrument specializes in collecting ultraviolet light to analyze the composition of Europa’s atmospheric gases and the materials on its icy surface.
Dr. Curt Retherford, principal investigator for Europa-UVS and a research scientist at the Southwest Research Institute, remarked, “This unexpected opportunity to observe another target on its journey to Jupiter has us very excited.”
“Our observations offer a distinctive and detailed view of the comet.”
Discovered on July 1, 2025, by the NASA-funded ATLAS survey telescope in Rio Hurtado, Chile, 3I/ATLAS was traveling at a heliocentric distance of 4.51 astronomical units (AU) with an eccentricity of 6.13 at that time.
Within a week of its discovery, the Jet Propulsion Laboratory’s analysts had determined its trajectory through the solar system.
The Europa Clipper team quickly identified that their spacecraft could view 3I/ATLAS in November 2025, especially after Earth-based observations were largely obstructed by the Sun’s position and Mars observations became optimal.
During this period, the spacecraft provided crucial data between the Mars observations in September and upcoming Earth-based exams.
With the comet’s trajectory aligning between Europa Clipper and the Sun, the UVS team was able to observe it from a distinctive angle.
Comets feature a dust tail that trails behind and a plasma tail that extends away from the Sun.
The Europa-UVS’s unique sunward perspective enabled a rare downstream view of the comet’s two tails, primarily observing from behind the tail and toward the comet’s core and coma.
“We anticipate that this new perspective, together with data from Earth-based assets and other spacecraft, will enhance our understanding of the tail’s shape,” stated Dr. Thomas Greathouse, co-principal investigator for the Europa-UVS study.
The UVS instrument identified signatures associated with oxygen, hydrogen, and dust, reinforcing evidence of significant outgassing activity from 3I/ATLAS shortly after its closest approach to the Sun.
“Europa-UVS excels at measuring fundamental transitions of atoms and molecules,” remarked Dr. Retherford.
“We can observe gas being expelled from the comet, along with water molecules splitting into hydrogen and oxygen atoms.”
This capability allows Europa Clipper to closely analyze and measure these atomic species, offering deeper insights into the comet’s processes and composition.
“By understanding the chemical makeup of comets and how readily these gases are ejected, we can better comprehend their origins and evolution as they traverse from distant parts of the galaxy to our solar system,” explained Dr. Tracy Becker, co-principal investigator for Europa and UVS, also at the Southwest Research Institute.
“What chemical processes occur? How can we grasp the origins of comets within our solar system?”
“Are these processes akin to our theories about the formation of the solar system? That’s a key question.”
Source: www.sci.news
