3I/ATLAS Revelation: Leaked US Docs Suggest CASSANDRA Quietly Tracked Comet for 20 Years

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. (Credit: 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.