GAO Report: Large Constellations of Satellites: Mitigating Environmental and Other Effects
There are almost 5,500 active satellites in orbit as of spring 2022, and one estimate predicts the launch of an additional 58,000 by 2030.
Large constellations of satellites in low Earth orbit are the primary drivers of the increase. Satellites provide important services, but there are potential environmental and other effects that this trend could produce (see figure).
GAO assessed technologies and approaches to evaluate and mitigate the following potential effects:
• Increase in orbital debris. Debris in space can damage or destroy satellites, affecting commercial services, scientific observation, and national security. Better characterizing debris, increasing adherence to operational guidelines, and removing debris are among the possible mitigations, but achieving these is challenging.
• Emissions into the upper atmosphere. Rocket launches and satellite reentries produce particles and gases that can affect atmospheric temperatures and deplete the ozone layer. Limiting use of rocket engines that produce certain harmful emissions could mitigate the effects. However, the size and significance of these effects are poorly understood due to a lack of observational data, and it is not yet clear if mitigation is warranted.
• Disruption of astronomy. Satellites can reflect sunlight and transmit radio signals that obstruct observations of natural phenomena. Satellite operators and astronomers are beginning to explore ways of mitigating these effects with technologies to darken satellites, and with tools to help astronomers avoid or filter out light reflections or radio transmissions. However, the efficacy of these techniques remains in question, and astronomers need more data about the satellites to improve mitigations.
GAO developed the following policy options to help address challenges with evaluating and mitigating the effects of large constellations of satellites. GAO developed the options by reviewing literature and documents, conducting interviews, and convening a 2-day meeting with 15 experts from government, industry, and academia. These policy options are not recommendations. GAO presents them to help policymakers consider and choose options appropriate to the goals they hope to achieve. Policymakers may include legislative bodies, government agencies, standards-setting organizations, industry, and other groups.
Policymakers may be better positioned to take action on this complex issue if they consider interrelationships among these policy options. For example, implementing the fourth option (improving organization and leadership) may improve policymakers’ ability to implement the first and second options (building knowledge, developing technologies, and improving data sharing). Similarly, implementing the first option may help with the third option (establishing standards, regulations, and agreements). More generally, trade-offs between mitigations may emerge, the ongoing increase in new constellations may introduce unexpected changes, and a large and diverse set of interests from the global community may shift over time, all of which present persistent uncertainties. To address these complexities and uncertainties, the full report presents the policy options in a framework, which may help policymakers strategically choose options to both realize the benefits and mitigate the potential effects of large constellations of satellites.
