PARIS — The Indian and Israeli governments on July 5 agreed to work together to develop atomic-clock technologies for satellite systems, a sore subject in India following the failure of several clocks aboard India’s regional satellite navigation system.
The two governments also agreed to perform a test of a laser-optical communications link between satellites in low Earth orbit and the higher geostationary orbit over the equator.
Meeting in Tel Aviv, the two heads of state agreed to a memorandum of understanding with respect to electric propulsion for small satellites as well.
The Indian Regional Navigation Satellite System (IRNSS) uses the same rubidium atomic frequency standard clocks as China’s Beidou global aviation system and Europe’s global Galileo positioning, navigation and timing network.
All were built by Oriola’s Spectratime of Switzerland. But the Chinese clocks were delivered before a defective component was introduced into the production run at Spectratime, sparing China the issues that have dogged both the Indian and European systems.
European officials said they have found the cause of the problem — a component introduced into a specific production series at Spectratime — and are replacing and repairing the clocks on satellites yet to be launched:
An unrelated issue on Spectratime’s hydrogen maser clocks — each Galileo satellite has two rubidium and two maser clocks on board — has been overcome by a shift in the way the clocks are operated from the ground, specifically in the way they are switched on and off.
India has been obliged to accelerate the launch of an IRNSS satellite to ensure the system’s operational integrity but, like Europe, apparently has not suffered a complete failure.
China has since developed a domestic supplier of atomic clocks for its Beidou network. Russia and the United States, which operate the two other global satellite navigation networks, also have their own supply base.
Israel and India may face the same industrial-policy problem as Europe. Diversifying the supply chain to have at least two manufacturers of all critical components is the desired outcome, but assuring that the selected manufacturers have enough business to survive is another matter.
European officials said building atomic clocks is not a business that attracts investors. Nonetheless, the European Commission and the 22-nation European Space Agency (ESA) are taking steps to assure at least a second source.
It could not be immediately determined whether India and Israel have selected a geostationary and a low-orbiting satellite to test an optical link.
Laser-optical intersatellite communications a focus
Space-based optical transmissions are the subject of active programs in Europe, the United States and China.
Europe appears to have made the most progress on the operational front, fitting some of its Sentinel Earth observation satellites with laser communications terminals to speed imagery to users via a high-speed laser link with a satellite in geostationary orbit.
The system is operational, and Airbus Defense and Space has been contracted to transform it into a commercial service called the EDRS – SpaceDataHighway.
Here is the text of the statement relating to space cooperation from the July 5 India-Israel summit:
“Both leaders welcomed the ongoing cooperation between the Israel Space Agency (ISA) and the Indian Space Research Organization (ISRO).
“They expressed satisfaction over the signing of three MoUs and Plan of Cooperation in the areas of Cooperation in Atomic Clocks; GEO-LEO Optical Link; Academic collaboration and Electric propulsion for small satellites which would further enhance cooperation between the two countries.
“They also encouraged the two Space Agencies to further enhance the growing relationship for mutual benefit. The two leaders acknowledged that the recent launching by ISRO of an Israeli nano satellite is an important milestone in this arena.”