About the Project

The Lexicon for Outer Space Security, developed by the United Nations Institute for Disarmament Research (UNIDIR) and the Secure World Foundation (SWF), is an essential reference tool designed to foster a shared understanding of key terminology in space security discussions. Recognizing that differing interpretations of terms can hinder international dialogue, the Lexicon provides clear, structured explanations of commonly used space security concepts. It does not impose singular definitions but instead highlights the variety of ways in which terms are understood across technical, legal, linguistics and policy contexts. By doing so, it aims to improve transparency, reduce misunderstandings, and enhance meaningful engagement in multilateral space security discussions.

This Lexicon was developed through a rigourous and inclusive methodology that analyzed terminology used in multilateral fora, including United Nations statements and documents. A geographically diverse expert group contributed to refining the terms and definitions, ensuring that linguistic and conceptual variations were accounted for. The result is a dynamic and evolving resource that serves as a global reference point for policymakers, diplomats, academics, and industry professionals navigating the complexities of space security. As space activities continue to expand, this Lexicon provides a foundation for more effective communication and cooperation in preserving the security, safety, and sustainability of outer space.

The development of the first edition of the Lexicon for Outer Space Security was generously supported by the Government of the Republic of Korea.

The United Nations Institute for Disarmament Research (UNIDIR) and the Secure World Foundation (SWF) would like to thank all those who contributed to this Lexicon. Laetitia Cesari, Anuradha Damale-Day, Sarah Erickson, Xavier Pasco, Daniel Porras, Rajeswari Rajagopalan, James Revill, Sami Shihadeh, Cassandra Steer, Dmitry Stefanovich and Guoyu Wang provided instrumental expert contributions. The editors would also like to acknowledge Phillippa Biggs, Veronique Glaude, Niklas Hedman, Michael Spies, Alexandre Vallet, and Wen Zhou for their critical feedback. The editors also thank Peter Martinez, Brian Weeden, and Christopher Johnson from Secure World Foundation for their invaluable advice and assistance, as well as Hellmut Lagos Koller for his support of this project.

Photo credit on the About Lexicon and Foreword page: SpaceX. All other photos employed on the website: NASA.

The designations employed and the presentation of the material in this publication do not imply the expression of any opinion whatsoever on the part of the Secretariat of the United Nations concerning the legal status of any country, territory, city or area, or of its authorities, or concerning the delimitation of its frontiers or boundaries. The views expressed in the publication are the sole responsibility of the individual authors. They do not necessarily reflect the views or opinions of the United Nations, UNIDIR, its staff members or sponsors.

Almudena Azcárate Ortega & Victoria Samson (Eds.) (2023). A Lexicon for Outer Space Security, UNIDIR, Geneva. Retrieved from https://spacesecuritylexicon.org