In an unprecedented international collaboration, NASA, the European Space Agency (ESA), and more than 23 nations have initiated the largest planetary defence exercise in history, using the passage of the interstellar object 3I/ATLAS as a real-world test case.
The drill, coordinated under the United Nations’ International Asteroid Warning Network (IAWN) and running from November 27, 2025, through January 27, 2026, marks the eighth such global observing campaign since 2017—but the first to centre on an interstellar object.
Discovered in July 2025 by the ATLAS survey in Chile, 3I/ATLAS is only the third confirmed visitor from outside our solar system, following ’Oumuamua and Borisov.
While officials emphasise that the object poses no threat to Earth—passing at a safe distance with its closest approach occurring around mid-December—the exercise is designed to sharpen humanity’s response to potential near-Earth object (NEO) hazards.
”This is a unique opportunity to practice detection, tracking, and characterisation on a fast-moving, real interstellar target,” said a spokesperson for IAWN.
The object’s high speed of approximately 60 km/s and unusual trajectory provide invaluable realism for refining orbital predictions and anomaly-response protocols.
Participating agencies, including NASA, ESA, ISRO (India), CNSA (China), and JAXA (Japan), are pooling data from ground-based telescopes in Hawaii, Chile, and Australia, alongside spacecraft observations from Mars orbiters like NASA’s Mars Reconnaissance Orbiter and ESA’s Mars Express and ExoMars Trace Gas Orbiter. Recent triangulation efforts using these assets have dramatically improved trajectory estimates, demonstrating the power of international data-sharing.
The exercise also includes simulations of deflection missions (inspired by NASA’s DART test), civil defence mobilisation, and public communication strategies—addressing gaps exposed by public interest and occasional misinformation surrounding the object’s brightness fluctuations and non-gravitational accelerations.
ESA’s Planetary Defence Office highlighted the drill’s timing with broader preparations, noting upcoming close approaches like the 2029 flyby of asteroid Apophis, which will be visible to the naked eye in parts of Europe. ”Public interest in planetary defense will be immense,” ESA stated, underscoring the need for transparent communication.
This massive drill comes amid heightened global investment in space safety. ESA recently secured a record €22.1 billion budget, boosting resilience initiatives, while agencies worldwide stress that planetary defence is ”no longer sci-fi” but a critical skill to hone.
As 3I/ATLAS continues its journey through the solar system, the exercise serves as a stark reminder of Earth’s vulnerability to cosmic threats—and the growing unity in facing them. Officials report the campaign is proceeding smoothly, with lessons learned set to strengthen future defences against asteroids, comets, and unknown space objects.
Sources
- NASA CNEOS: Planetary Defense Conference Exercise – 2025 (The 2024 PDC25 Hypothetical Asteroid Impact Scenario, Epoch 2: April 28, 2028)
- NASA: Centre for Near Eartch Space Objects
- NASA: Planetary Defense at NASA
- NASA: Planetary Defense Interagency Working Group
- The International Academy of Astronautics: IAA Planetary Defense Conference 20255-9 May 2025
- Daily Mail: Space agency activates its largest planetary defense drill as interstellar visitor approaches Earth
- New York Post: Space agencies conducting largest ever planetary defense drill with 3I/ATLAS approaching