Earlier this month, a discarded SpaceX Falcon 9 upper stage crashed into the lunar surface at 8,700 kilometers per hour. This was not a controlled landing. The stage had been drifting, out of fuel and out of control, for 19 months since it delivered Firefly’s Blue Ghost and ispace’s Resilience landers to the moon in January 2025. This time, it hit an empty stretch on the lunar surface, approximately 900 kilometers (550 miles) away from any other structures. However, this may not always be the case. By 2030, both the United States and China anticipate crewed landings on the lunar surface. With a mere two to four years until those landings are scheduled to occur, there is minimal time to coordinate lunar safety guidelines to not only protect robotic missions, but also the human lives and infrastructure needed for long-duration crewed missions.

The impact, although only one of two recent uncontrolled upper stage crash landings on the lunar surface, highlights the broader lack of lunar disposal guidelines. Today, the only international guidelines which govern lunar disposal are the COSPAR planetary protection guidelines. They exist to limit biological and organic contamination of scientifically sensitive sites, mainly in the poles and permanently shadowed regions, not to govern the impact of uncontrolled landings. Lunar surface disposal has substantial potential to impact surrounding operations. In addition to the risk of direct impact, the ejection of debris is a major risk. It is possible for debris to be ejected into cislunar orbit; even for controlled descents during the Apollo era, Plume Surface Interactions sent debris several kilometers from the landing site. Hazardous materials onboard are also a concern; the potential fuel contamination from overflight has been considered in landing site selection, and efforts are being made to establish nuclear safety standards alongside the push for the development of lunar nuclear reactors.

Although it seems doubtful that international legally-binding guidelines surrounding lunar disposal will develop soon, the topic is included in Artemis Accords Principle 12, and has received substantial attention from several nations with lunar capabilities. The UK Space Agency provided an analysis of post-mission disposal options for three lunar orbits, finding that semi-controlled impact, heliocentric transfer and deep space transfer were lowest risk and cost. JAXA awarded ispace a contract this year to study private sector perspectives on lunar debris and disposal management. The South Korean government has sponsored multiple international events related to lunar coordination, and broadly flagged cislunar space traffic coordination as an issue.

Despite a lack of momentum toward a new legal framework, there are substantial mechanisms that can be taken now to mitigate harm from cislunar activity. International standards and technical bodies are key to encourage coordination, particularly with the inclusion of China and Russia in organizations such as the Inter-Agency Space Debris Coordinating Committee (IADC), International Standards Organization (ISO), Consultative Committee on Space Data Systems (CCSDS) and International Space Exploration Coordination Group (ISECG). The IADC Space Debris Mitigation Guidelines, as well as the U.S. Orbital Debris Mitigation Standard Practices, notably have an xGEO and cislunar void in any basic guidance on disposal. Although it remains highly unlikely that is possible to avoid even intentional crash landings on the lunar surface given the lack of alternate viable options for disposal of satellites in low Lunar orbit, guidance on controlled disposals on the lunar surface could be a starting point, as could guidelines surrounding disposal of objects already on the lunar surface regarding passivation and human safety.

Transparency is also key to mitigating the harm from lunar activity. Artemis Accords signatories have agreed to submit additional registration parameters to the UN Office of Outer Space Affairs, including post-mission disposal plans. NASA has left many of the parameters in its lunar registrations as “Defer to Commercial Provider”, while simultaneously not providing an avenue for commercial providers to submit this missing information, presumably due to a lack of comprehensive mission authorization and supervision regime to provide oversight for commercial lunar activities. Governments have the opportunity to build in requirements for post-mission disposal during mission development and contracting; NASA already requires an Orbital Debris Assessment Report of its contracted missions, which requires the submission of a post-mission disposal plan.

Finally, data collection and data-sharing are of the utmost importance in better understanding the impacts of cislunar activity. South Korea’s Danuri spacecraft captured the SpaceX upper stage impact, providing crucial data. Even for controlled impacts, very little is known about the impact of engine size or configuration, changes in impact based on terrain, physical changes to the surface, particle distribution, or potential mitigation mechanisms such as landing pads. Ensuring the collection of data, including through the use of standardised sensor suites such as Stereo Cameras for Lunar Plume-Surface Studies (SCALPSS), and encouraging operators to share lessons learned internationally through venues such as standards bodies, COPUOS and the Artemis Accords will be vital to ensuring the safety and sustainability of lunar missions for all.

Juliet Hannay is a communications officer at the European Space Policy Institute.

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