On October 3, 2025, the interstellar object 3I/ATLAS came within 29 million kilometers of Mars. The highest resolution images of 3I/ATLAS were obtained by the HiRISE camera onboard the Mars Reconnaissance Orbiter. This camera with a 50-centimeter aperture reached a spatial resolution of 30 kilometers per pixel, about 3 times better than the Hubble Space Telescope image from July 21, 2025 (accessible here).
Yesterday, the brilliant congresswoman Anna Paulina Lune tweeted the following message:
This follows a DEFENSESCOOP news report titled “US government grapples with questions about interstellar object 3I/ATLAS amid shutdown”, accessible here.
While we are all waiting for the end of the U.S. government shutdown and the release of the HiRISE images of 3I/ATLAS, China National Space Administration (CNSA) released here images obtained on October 3, 2025 by the Tianwen-1 Mars Orbiter at a distance of 28.96 million kilometers from 3I/ATLAS.
The Tianwen-1 orbiter entered Mars orbit in February 2021. Its High-Resolution Imaging Camera (HiRIC), described here, employs a primary mirror diameter of 38.7 centimeters, with an inferior resolution relative to the 50-centimeter aperture of the HiRISE camera. The released HiRIC images show the nucleus and a surrounding coma with a diameter of several thousand kilometers. The CNSA researchers generated an animation of the trajectory of 3I/ATLAS in the Martian sky based on a series of 30-second images, available here.
Here’s hoping for better images from NASA’s HiRISE in the coming days.
ABOUT THE AUTHOR
Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024.
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