The issue of near-Earth objects (NEOs) has long been on the agenda of the Committee on the Peaceful Uses of Outer Space (COPUOS), the primary United Nations body for coordinating and facilitating international cooperation in space activities, established in 1959 by the UN General Assembly and supported by the Office for Outer Space Affairs (UNOOSA). In the last year several important events have contributed to our understanding of NEOs and to a better preparedness in case of a real impact threat.

The International Asteroid Warning Network (IAWN) and the Space Mission Planning Advisory Group (SMPAG) provide mechanisms at the global level to address the global challenge posed by NEOs, including detection, tracking and impact risk assessment and, subsequently, planetary defence measures like civil protection or asteroid deflection.

UNOOSA, through the IAWN and SMPAG, facilitates the dissemination of information related to NEOs to UN Member States. Important linkages are being made with civil protection communities, including through UNOOSA’s UN-SPIDER programme and its global network of Regional Support Offices (RSOs).

IAWN and SMPAG - global mechanisms for coordinating action in the area of planetary defence

The IAWN links together the institutions that are already performing many of the proposed functions, including: discovering, monitoring and physically characterizing the potentially hazardous NEO population. One of its purposes is to maintain an internationally recognized clearing house for the receipt, acknowledgment and processing of all NEO observations. IAWN recommends policies regarding criteria and thresholds for notification of an emerging impact threat. IAWN also assists Governments in the analysis of impact consequences and in the planning for mitigation responses, using well-defined communication plans and protocols (see As at June 2021, there are thirty-two official signatories to the IAWN Statement of Intent.

The SMPAG, (pronounced “same page”) is composed of Member States with space agencies or inter-governmental entities that coordinate and fund space activities and are capable of contributing to or carrying out a space-based NEO mitigation campaign. In the event of a credible impact warning by the IAWN, the SMPAG would assess and propose through their member Governments space-based mitigation options and implementation plans for consideration by the Member States. 

SMPAG currently has 19 members and 6 permanent observers, with UNOOSA acting as its secretariat. In 2016, SMPAG established the Ad-Hoc Working Group on Legal Issues to address possible legal questions related to the work of SMPAG. This group published a report entitled ´Planetary Defence Legal Overview and Assessment´ (see under ´Documents and presentations´).

International Asteroid Day

As part of the effort to raise awareness about this topic, the UN General Assembly proclaimed in resolution A/71/492 that International Asteroid Day would be observed annually on 30 June to raise public awareness of the asteroid impact hazard. 30 June is the anniversary of the Tunguska impact over Siberia in what is now the Russian Federation, which occurred on 30 June 1908. That event was Earth’s largest confirmed asteroid impact in recorded history, devastating over 2,000 square kilometres of forest.

International Planetary Defense Conference (PDC) 2021

As the key biannual global conference that brings together key experts in this area, the 7th International IAA (International Academy of Astronautics) PDC was hosted by UNOOSA from 26 to 30 April 2021 as a virtual conference that attracted wide audience, with more than 700 participants from all over the globe. Highlight presentations included results from the sample return space missions Hayabusa2 (lead by JAXA)  and OSIRIS-REx (lead by NASA) and latest status information on the upcoming missions DART and HERA which will demonstrate the capability to deflect an asteroid by the kinetic impactor technique. The 2021 PDC also included a number of dedicated panels on different aspects of Planetary Defence. In a panel with Heads and Representatives of Space Agencies, 11 high ranked officials (from AEB,  AEM, Austrian Space Agency FFG, CNSA, ESA, KASI, NASA) gave statements and expressed their support for international collaboration on Planetary Defence issues.

As in previous PDCs, a hypothetical asteroid impact scenario was part of the Conference. This time the scenario included  a hypothetical impactor of approximately 100 m in size discovered only six months before impact. Due to the imposed short warning time, a space mission for deflection was not possible. The main emphasis of this exercise was an assessment of impact effects and the role, interaction and mitigation measures from civil protection agencies. Several disaster management representatives from both national, regional and intergovernmental levels (Copernicus EMS, ERCC, FEMA, UN-SPIDER, UNOSAT) were engaged in discussing practical solutions to this hypothetical asteroid scenario that was initially predicted to pose a threat to most parts of Earth and eventually impacted the border areas of Austria, Czech Republic and Germany. The next PDC will be held in 2023 and hosted again by UNOOSA in Vienna as an in-person or hybrid meeting.

Presentations and recordings of the 7th IAA PDC 2021 are available here.