NASA Will Release HiRise Images of 3I/Atlas Interstellar Object Tomorrow

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NASA has officially announced a live event on Wednesday, November 19, 2025, at 3:00 p.m. EST where they will share these HiRISE images along with other new data and visuals from Hubble, SPHEREx, and additional spacecraft/telescopes.

NASA’s HiRISE instrument, on the Mars Reconnaissance Orbiter, captured the highest-resolution images of the interstellar comet 3I/ATLAS as it passed Mars in October 2025. These images, which are expected to be released on November 19, 2025, are anticipated to be clearer than previous images taken by the Hubble Space Telescope.

Why This Matters for 3I/ATLAS

The comet’s nucleus is estimated at 1–5.6 km across, but the coma, dust cocoon, sunward anti-tail and any jets are extended features tens to hundreds of km in size. HiRISE’s 30 km/pixel allows far clearer mapping of these structures — especially from the advantageous side-view geometry — than Hubble’s blurrier, edge-on perspective in July. HiRISE is expected to be the sharpest view of 3I/ATLAS we’ve ever had, roughly three times higher resolution than the famous July Hubble images, with a much better angle on the comet’s anomalous features

This could tell us the diameter of the nucleus (better inference based on what we will be able to image) and understand the geometry of the anti-tail from 3I/ATLAS towards the Sun. The previous high-resolution image was obtained by the Hubble Space Telescope on July 21, 2025.

The images should have a spatial resolution of ~30 kilometers per pixel and a side view of the anti-tail and jets from 3I/ATLAS on October 2–3, 2025, when it came within 29 million kilometers from Mars. Sharing of scientific data should have been prioritized over bureaucratic rules, because the data is time-sensitive as we plan additional observations of 3I/ATLAS.

A different solar system comet larger than Lake Erie and ten thousand times more massive than 3I/ATLAS, is moving towards the Sun from the Oort cloud.

C/2014 UN271 or Comet Bernardinelli–Bernstein (nicknamed BB) was first imaged 29 times farther away from the Sun than the Earth is (29 AU = 4.3 billion kilometers), almost as far as Neptune. This represented the largest distance at which a comet has ever been discovered. The nucleus diameter of C/2014 UN271 is larger than 100 kilometers, making it the largest Oort cloud comet known. Its closest approach to the Sun will reach a minimum separation of 10.9 AU — just outside of Saturn’s orbit, in January 2031. It originated at a distance of order 40,000 AU about 1.4 million years ago.