The return link seems to be part of the EU's Galileo GNSS system, which has SAR components to it generally, and this is a new one: * https://www.euspa.europa.e

The return link seems to be part of the EU's Galileo GNSS system, which has SAR components to it generally, and this is a new one: * https://www.euspa.europa.eu/newsroom/news/galileo-return-link-service-declared-european-space-conference https://www.euspa.europa.eu/newsroom/news/galileo-return-lin... Galileo's implementation actually seems to have entered "full operational capacity" a few months ago: * https://ec.europa.eu/defence-industry-space/galileosar-unique-feature-return-link-enters-full-operational-capacity-just-one-year-after-its-2021_en https://ec.europa.eu/defence-industry-space/galileosar-uniqu... The US has officially approved use of the appropriate spectrum (406 MHz) as well: * https://www.federalregister.gov/documents/2021/02/08/2021-02509/return-link-service-authorization-in-the-united-states-search-and-rescue-region https://www.federalregister.gov/documents/2021/02/08/2021-02...