NavIC non-operational on account of failure of atomic clocks
Time is running out for the seven-satellite Indian Regional Navigation Satellite System (IRNSS), also known as NavIC (Navigation in Indian Constellation). NavIC, whose seventh satellite was launched in April 2016, was expected to provide India a satellite-based navigation system independent of the U.S.-controlled GPS (Global Positioning System). But India’s own ‘regional GPS’ is yet to become officially operational owing to repeated failures of the atomic clocks on the satellites.
Plan of buffer satellites
In view of the cascade of failing imported atomic clocks — nine out of the 21 clocks in the fleet have failed — ISRO has decided to add buffers to the NavIC by adding four more satellites. It hopes to have an indigenous atomic clock in each of them. NavIC is meant to give Indian civil and military users reliable location and time information, for which the performance of the atomic clocks is critical.
Where are indigenous clocks being developed?
The indigenous atomic clock is being developed by the Space Applications Centre, Ahmedabad, Mr. Sivan said, adding that once it passes qualification tests, “We will first demonstrate the indigenous clock in an upcoming navigation satellite, along with the imported ones. Work on them is going on in full steam.”
Failure of rubidium clocks
The rubidium atomic clocks from Europe started failing on the first navigation satellite, IRNSS-1A, around 2016, soon after ISRO put the last and seventh satellite in orbit. Until a few months ago, three more satellites were said to have suffered “one or two dysfunctional clocks” each, while two satellites did not have any problematic clocks. Each satellite carries three atomic clocks, including a standby.
ISRO is concerned that if more clocks fail, it may render the Rs.1,400-crore fleet a dud in space. NavIC, which will be controlled solely by India, unlike the American GPS or Russian Glonass navigation systems, will be useful as navigation aids for the armed forces.
(Adapted from The Hindu)