The World Radiocommunication Conference 2023 (WRC-23) established a comprehensive agenda for WRC-27, addressing critical issues in satellite, terrestrial, and scientific services. Among the 19 agenda items, five focus on scientific services, including lunar communications, radio astronomy protection, space weather sensors, and Earth exploration services. This paper examines these agenda items, detailing the studies mandated by resolutions to ensure efficient spectrum allocation and protection against harmful interference. Key topics include the development of lunar communication systems, safeguarding radio astronomy through Radio Quiet Zones (RQZs), protecting passive sensors for space weather and Earth observation, and optimizing allocations for sea surface temperature (SST) measurements. The studies, guided by ITU-R study groups, aim to balance technological advancements with the protection of critical scientific activities. By promoting international cooperation and sustainable spectrum use, these efforts will support future regulatory decisions and enable a resilient global radiocommunication ecosystem.

Space weather monitoring depends critically on passive sensor systems that detect and measure natural solar and geospace emissions without transmitting radio frequency energy. These include riometers, solar radio monitors, interplanetary scintillation detectors, GNSS-based ionospheric sensors, and broadband solar spectrographs that enable the provision of critical data required to forecast geomagnetic storms, protect critical infrastructures, and support aviation services, satellite operations, and defense services. However, with the increasing proliferation of radiocommunication technologies such as 5G/6G networks, dense HF/VHF/UHF deployments, and large constellations of low-Earth-orbit (LEO) satellites, the interference threat to these exceptionally sensitive receivers has grown. Most of these operate near the thermal noise floor and thus require strict protection criteria to ensure continuity of data. This review and perspective article provides a cross-disciplinary synthesis of scientific requirements, documented RFI case studies, and ongoing regulatory developments related to spectrum protection for passive space weather sensors. It systematically integrates perspectives on physical, technical, and regulatory aspects that are typically addressed separately in the literature. The article reviews the operating principles of major sensor classes and analyzes documented RFI cases affecting GNSS, riometers, CALLISTO, BINGO, and systems impacted by LEO satellite emissions, drawing from existing reports and regulatory submissions. Building on this evidence base, the work comparatively evaluates regulatory methods under consideration for WRC-27 shows that hybrid approaches combining primary allocations in core observation bands with secondary status and coordination procedures in adjacent bands offer the most viable path forward. This synthesis contextualizes and analyzes how technical protection criteria can be integrated with existing and evolving regulatory instruments to inform spectrum governance. The study concludes that without coordinated international spectrum management incorporating explicit protection thresholds and registration procedures, the long-term viability of space weather monitoring infrastructure faces significant risk in an increasingly congested radio frequency environment.

This document shows an analysis of the existing challenges for a safe and sustainable use of space, given the significant increase in the number of Low Earth Orbit satellites in recent years. An analysis of the number of objects launched into outer space from 1957 to 2023 is presented, as well as a growth projection by the year of 2035. The international historical context of space sustainability and the challenges for properly addressing the topic are also addressed. More studies are needed to develop an effective approach for both scenarios, nationally and internationally.

Space sustainability has become a critical issue as the increasing number of orbital objects poses significant risks to space-based services, scientific research, and technological progress. Key challenges include space debris, radio frequency interference (RFI), and orbital congestion, which jeopardize essential scientific activities such as Earth observation, meteorology, and radio astronomy. International organizations, including the United Nations (UN), the International Telecommunication Union (ITU), and the Committee on the Peaceful Uses of Outer Space (COPUOS), have developed frameworks to address these challenges through debris mitigation, spectrum management, and collaborative guidelines. This paper explores the historical evolution and current challenges of space sustainability, emphasizing the importance of international cooperation in implementing sustainable practices. Initiatives such as the ITU's Best Practices Handbook, the COPUOS 2018 Guidelines, and the Dark and Quiet Skies (DQS) project highlight global efforts to preserve orbital and spectral resources. Advancing Space Situational Awareness (SSA) capabilities, fostering international collaboration, and strengthening regulatory frameworks are identified as key priorities to ensure the long-term usability of outer space and the continuity of vital scientific services.