Atomic clocks failure: ISRO decides to replace IRNSS-1A with backup navigation satellite

Three atomic clocks on board ISRO's IRNSS-1A satellite have failed following which the space agency has decided to launch a standby navigation satellite. 

ISRO will be launching the backup navigation satellite this year and it will replace the IRNSS-1A, an official of the space agency confirmed on Monday.

The official said similar problems do not exist with the rubidium atomic clocks in another navigation satellite. 

"The atomic clocks have failed in only one satellite. We will be launching the stand-by satellite this year. All other six satellites are operational and are providing the navigation data," AS Kiran Kumar, Chairman, Indian Space Research Organisation (ISRO), said.
Kumar said that ISRo will take up the snag issue with the foreign supplier as the atomic clocks were important.

The same vendor had supplied a total of 27 clocks for the navigation satellite system and each satellite carries three clocks. In order to obtain precise data, the clocks are important.

The Indian Regional Navigation Satellite System (IRNSS) is just like the GPS (Global Positioning System) of the US, Glonass of Russia and Galileo of Europe as well as China's Beidou.

The GPS and Glonass are fully functional systems, while the Chinese and Japanese ones provide regional coverage. Galileo of Europe is not operational yet.

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ISRO says IRNSS offer terrestrial, aerial and marine navigation, vehicle tracking and fleet management, terrestrial navigation for hikers and travellers, disaster management, integration with mobile phones, mapping and geodetic data capture and visual and voice navigation for drivers. IRNSS, in other words, can be called as the 'Indian GPS'.

The IRNSS, apart from providing civilian applications, will also be used for defence purposes. According to Kumar, ISRO is studying the snag.

Indian satellite navigation system NavIC, worth Rs 1,420 crore, consists of 7 satellites in orbit and two as substitutes.

ISRO has launched all the 7 satellites starting in July 2013, with the last being launched on April 28, 2016. Each satellite has a span of 10 years.

All the 7 satellites were working fine until the three clocks in the first satellite – IRNSS-1A – failed.

All the hardware are susceptible to failure even though elaborate testing is done, said Kumar. According to industry officials, navigation satellites of other countries too have faced similar issues.