3I/ATLAS during its October flyby of Mars
NASA released images of interstellar comet 3I/ATLAS during its October flyby of Mars, a rare event that saw the third known interstellar object pass within 30 million kilometres of the Red Planet. NASA

When 3I/ATLAS entered our inner Solar System in late 2025, astronomers across the world scrambled to observe it. But as public fascination grew, so did a wave of online speculation. Unverified documents and leaked images circulating on forums now claim that a classified US planetary defence system known as CASSANDRA had been tracking the object for decades.

While no space agency has confirmed the existence of such a programme, the allegations have ignited intense debate about what governments may know about interstellar visitors long before the public does.

Why NASA's Silence Fuelled Suspicion

Following 3I/ATLAS's detection, agencies in Europe, Asia and South America released imagery and observational data. NASA's comparatively limited public commentary became a focal point for speculation. Online commentators suggested the absence signalled prior knowledge, though astronomers caution that operational silence does not indicate secrecy and can reflect verification protocols.

No official statement from NASA or the US Department of Defence has acknowledged advance tracking of 3I/ATLAS.

The Alleged 'CASSANDRA' Connection

On 2 November 2025, a Medium article cited forum posts featuring two images labelled 'CASSANDRA / ORACLE VI ARGUS-VIS" and "C/2025 N1 UMBRA-3/C'. The photos, whose origins remain unverified, allegedly show structured plasma emissions and geometric radiation patterns.

The first one showed a high-resolution, black-and-white image of a bright core with structured emissions. The second one is the opposite of the first. It showed a green coma with a glowing white-pink core, and the plasma streams were clear and radiating in patterns. The amateurs watching the sky said the release of gas and dust from the formations was unlike any comet they had seen.

Independent astronomers also verified that the object's trajectory showed unusual angular offsets. They suggest that other forces, besides gravity, were guiding its path. The mysterious part of the pictures is that they originated from a source called 'Cassandra'.

A 2005 Paper That Sparked Renewed Interest

Speculation intensified after users referenced a 2005 paper presented at the International Astronautical Congress in Valencia, Spain, titled 'Cassandra: A Strategy to Protect Our Planet from Near-Earth Objects'. The paper proposed a hypothetical early-warning network combining radar, satellites, and extreme mitigation options for asteroid threats.

Crucially, the paper described a conceptual framework rather than a deployed system. Experts stress that no evidence has emerged to show that CASSANDRA was ever funded, built, or operationalised.

The 2005 publication discussed dangers approaching Earth, but it also suggested that people would realise it only after the system was already in operation.

Why the Name 'Cassandra' Matters to Conspiracy Theorists

In Greek mythology, Cassandra foresaw disaster but was never believed. Online theorists argue that the name suggests hidden warnings that the public ignores. Historians of science note that mythological naming is standard in academic proposals and does not imply secrecy or prophecy.

Cassandra was a global planetary defence system implemented through radar, satellites, and a nuclear option if necessary.

The summary sounded like a prophecy from the past: 'detect very distant threats and track them continuously'. Cassandra was also built to be 'always aware' of an interstellar object's location from beyond geosynchronous orbit.

The name was not something ordinary either. According to Greek mythology, Cassandra predicted the fall of Troy, but nobody believed her. Similarly, the scientists involved in this project probably imagined that their work would be kept under wraps for a long time before it was actually used.

Claims of 'Unnatural' Behaviour Remain Unproven

Some online analysts claim leaked imagery shows plasma streams forming geometric patterns and non-gravitational trajectory adjustments. Astrophysicists contacted by mainstream outlets counter that such claims lack calibrated data and ignore known cometary physics, including outgassing jets and radiation pressure.

No recognised observatory has corroborated claims of artificial control or monitoring experiments.

What Is Actually Known About 3I/ATLAS

Confirmed observations show that 3I/ATLAS is the third known interstellar object detected passing through our Solar System. Its speed, trajectory and chemical signatures are consistent with an extrasolar origin. Beyond that, evidence supports a natural cometary body, not an engineered object or surveillance target.

Speculation Versus Science

While the idea of a hidden planetary defence network tracking interstellar visitors captures the imagination, experts stress the importance of separating conjecture from evidence. At present, CASSANDRA remains a theoretical concept, and claims of decades-long monitoring of 3I/ATLAS are unverified.

As with past interstellar visitors, scientists say the object's actual value lies in what it can teach about other star systems — not in secret programmes that exist only in leaked screenshots and online forums.

Writer's Pick