On December 27, 2024, asteroid 2024 YR4 was detected by a Chilean robotic telescope and, although initially considered unlikely to impact Earth, its risk probability rose over time, triggering UNOOSA's first global notification since the 2013 planetary defense collaboration.

The heightened threat level of 2024 YR4 reached Torino Scale level 3, opening discussions about mitigation options, including deflection via an intercepting spacecraft, building on lessons from NASA's 2022 DART mission.

Aarti Holla-Maini, director of UNOOSA, is the designated official authorized to alert the UN secretary-general and all 193 member states if a significantly large asteroid threatens Earth, a role she has rehearsed for despite doubts it would ever be needed.

By late January 2025, Romana Kofler coordinated with the International Asteroid Warning Network and other bodies to draft and send the alert to the UN secretary-general as a practical test of international coordination.

The 2024 YR4 scare served as a real-world stress test for UNOOSA’s planetary defense responsibilities, and monitoring later indicated the asteroid's risk had diminished to negligible levels, underscoring ongoing vigilance with limited resources.

A notable governance challenge arose when Malaysia alerted UNOOSA about a potential collision with a North Korean satellite; the lack of direct channels forced UNOOSA to broadcast information broadly, highlighting space traffic management complexities.

Despite its small size—about 35 staff in Vienna—UNOOSA continues to register satellites, support disaster response through UNOOSA-Spider, and act as an informal hotline for potential collisions, coordinating with a wide range of actors including states with limited diplomatic ties.