In October 2025, NASA's Mars Reconnaissance Orbiter (MRO) is scheduled to conduct a significant observational campaign focused on the interstellar comet 3I/ATLAS. The MRO will utilize its High Resolution Imaging Science Experiment (HiRISE) camera to study this celestial visitor.
The comet 3I/ATLAS was discovered on July 1, 2025, by the ATLAS telescope system in Chile. It is the third confirmed interstellar object to pass through our solar system, following 'Oumuamua in 2017 and Comet Borisov in 2019. Initial estimates place the comet's nucleus diameter between approximately 320 meters and 5.6 kilometers. Observations from the Hubble Space Telescope on July 21, 2025, revealed a coma of gas and dust, but notably, no distinct tail.
Recent studies have detected water activity within 3I/ATLAS, with a water production rate estimated at 40 kilograms per second when it was 3.51 astronomical units from the Sun. The comet's trajectory is highly hyperbolic, with an eccentricity exceeding 6.1, confirming its origin from outside our solar system and its unbound nature to the Sun.
On October 3, 2025, 3I/ATLAS is predicted to pass within 28.96 million kilometers of Mars. This proximity offers a prime opportunity for the MRO, already in Martian orbit, to perform detailed observations. Observing the comet from Earth will be challenging during this period due to its proximity to the Sun.
The ATLAS system, a global network of four robotic telescopes, has been instrumental in detecting such objects. Congresswoman Anna Paulina Luna has expressed support for astrophysicist Avi Loeb's proposal to potentially use the Juno probe to intercept and study 3I/ATLAS in March 2026. This combined observational approach, involving both the MRO and potentially the Juno mission, is expected to significantly enhance our understanding of interstellar objects and their origins.
The HiRISE camera, known for its ability to capture Martian surface details as small as a kitchen table, will provide high-resolution imagery of 3I/ATLAS, contributing valuable data to the scientific investigation of this rare cosmic visitor.