PARIS — The search-and-rescue (SAR) payload aboard one of Europe’s in-orbit Galileo positioning, navigation and timing satellites has been switched on and is performing to specification, with an identical payload aboard a second satellite to be activated in the coming weeks, the European Space Agency (ESA) said Jan. 24.

All 30 Galileo satellites, scheduled for launch in the coming years to medium Earth orbit at 23,222 kilometers in altitude, will be fitted with SAR transponders that will pick up signals from individuals or ships or planes in distress and forward them to regional first responders.

The system will be made part of the 43-nation Cospas-Sarsat consortium, which up to now has used satellites in low Earth orbit and in higher geostationary orbit. One key new feature of the Galileo SAR system is its ability to send messages to users confirming that their distress signal has been received.

Four Galileo satellites are in orbit, but only the second pair, launched in October 2012, is equipped with the SAR transponders. China originally was supposed to provide the Galileo SAR package, but these plans were scrapped when the European Commission, which owns Galileo, decided that China would not be permitted to have an active payload on the satellites. ESA is technical manager for Galileo on behalf of the commission.

For the first two Galileo satellites, the Chinese gear was removed and replaced with dummy payloads.

Mier Comunicaciones and Rymsa, both of Spain, provided the hardware on the SAR-equipped satellites now in orbit, with Norspace of Norway selected to provide the SAR transponders on the follow-on Galileo satellites, scheduled for launch starting late this year.

Peter B. de Selding was the Paris Bureau Chief for SpaceNews.