The European Space Agency (ESA) is using its Mars and Jupiter missions to monitor a fascinating interstellar comet named 3I/ATLAS. This comet, spotted in July 2025 by an ATLAS telescope in Chile, is special because it came from outside our solar system. Its unusual path, which doesn’t orbit the sun like most comets, combined with its speed of 130,000 mph (219,000 km/h), confirms its extrasolar origin.
3I/ATLAS will be visible to ground telescopes until September 2025. After that, it will move too close to the sun for us to see it clearly. Scientists want to study its size and composition, which could reveal insights about what interstellar comets are made of. By using ESA and NASA spacecraft already in orbit around the inner solar system, researchers hope to continue observing the comet even when it’s out of reach from Earth.
In early October 2025, Mars orbiters, including Mars Express and the ExoMars Trace Gas Orbiter, will have a close view of 3I/ATLAS as it approaches Mars. ESA estimates that these spacecraft will be as close as 30 million kilometers to the comet on October 3. The NASA Psyche mission, which is en route to asteroid 16 Psyche, will also catch glimpses of this cosmic traveler.
Later in November, ESA’s Jupiter Icy Moons Explorer (Juice) will study 3I/ATLAS right after it reaches perihelion, its closest point to the sun. This is a critical moment because the sun’s heat will cause the comet’s ice to vaporize, creating a visible halo of gas and dust. Observations during this period are expected to yield the most valuable data. T. Marshall Eubanks, Chief Scientist at Space Initiatives Inc, mentioned that Juice’s data will provide crucial insights when observations from Earth become challenging.
Observing 3I/ATLAS as it heats up will help scientists identify its chemical makeup. If its chemistry resembles that of comets from our solar system, it may indicate that planetary systems across the galaxy share similar building blocks. Conversely, any differences could point to unique ingredients from another star system. This duality makes the upcoming observations particularly exciting.
Data from these missions will enhance our understanding of interstellar comets and offer a peek into the materials that form planets and moons beyond our own solar system. As the scientific community gears up for this rare opportunity, researchers hope to uncover more mysteries hidden within the cosmos, illustrating how interconnected our universe might truly be.
