3I/ATLAS Updates: How the Hera Space Probe Fits into the Buzz Surrounding the Interstellar Comet

The intensifying scientific debate surrounding the interstellar object 3I/ATLAS has renewed focus on the European Space Agency (ESA) and its Hera mission, which is currently en route to validate humanity's capability to deflect celestial threats.

While 3I/ATLAS passes through the inner Solar System, the Hera spacecraft represents the next phase of planetary defence, tasked with analysing the kinetic impact techniques that might one day be required to intercept such unpredictable visitors.

Hera and the Legacy of DART

First launched on 7 October 2024, the Hera spacecraft is being described as the most sophisticated planetary defence probe yet deployed. Its current trajectory is set toward Dimorphos, the small moonlet of the Didymos system, with a rendezvous scheduled for December 2026.

Hera's journey comes in the wake NASA's Double Asteroid Redirection Test (DART) spacecraft and Dimorphos. The spacecraft struck the asteroid at four miles per second on 26 September, 2022. Hera's mandate is to conduct a detailed post-impact crime scene investigation, measuring the crater and the mass of the asteroid to determine the precise efficiency of the momentum transfer.

This data is critical for calibrating future missions. Should an object like 3I/ATLAS ever pose a direct threat to Earth, the kinetic impactor method refined by Hera would likely be the primary line of defence.

Why the Hera Probe is Significant to the Study of 3I/ATLAS

While Hera focuses on asteroids, the study of 3I/ATLAS has revealed behaviour that challenges standard cometary models. Harvard astronomer Avi Loeb has highlighted instances of non-gravitational acceleration, referring to a forward thrust that is not consistent with standard sublimation models.

Loeb argues that the object's movement suggests artificial propulsion rather than natural outgassing.

In an analytic piece, Samuel Lopez reiterates: 'In previous images I analysed, the jets did not align with the expected sunward-rearward dynamic; instead, they projected laterally and symmetrically, more akin to engineered and thrust nozzles than volatile outgassing'.

Combined with documented brightness surges, rotational patterns, and the anomalous UV halo measured by MAVEN, each feature layers onto the next, forcing us to evaluate 3I/ATLAS not as a passive traveller but as an active system that appears to regulate its motion,' said Lopez, referring to the NASA probe.

The intersection of these two narratives—Hera's navigation technology and 3I/ATLAS's erratic path—underscores the need for autonomous systems in deep space. Hera's systems will demonstrate 'the physics of altering an asteroid's motion', becoming the first to 'autonomously navigate a binary asteroid system'.

Cryovolcanism and Trans-Neptunian Origins

Recent observations have provided an alternative, natural explanation for the comet's erratic behaviour. Astronomers suggest that 3I/ATLAS may be covered with erupting 'ice volcanoes'.

In a study posted on 24 November on arXiv, researchers suggested that the comet may be similar to Trans-Neptunian Objects.

If confirmed, this classification would imply that despite its interstellar origin, 3I/ATLAS shares a compositional lineage with the icy bodies formed at the fringes of our own system.

'We were all surprised,' Josep Trigo-Rodriguez, the study's lead researcher at the Institute of Space Sciences in Spain, told Live Science. 'Being a comet formed in a remote planetary system, it is remarkable that the mixture of materials forming the surface of the body has resemblance with trans-Neptunian objects, bodies formed at distance from the sun but belonging to our planetary system.'