ISRO is working on the IRNSS-1I, a replacement satellite to complete India's navigation constellation

**ISRO** researchers are working on a replacement satellite IRNSS-1H for India’s own navigation satellite system, similar to the American Global Positioning System, the Russian GLONASS, the European Galileo and the Chinese Beidou. The satellite has been dubbed the IRNSS-1I, and will provide the same functionality that the IRNSS-1H would have. The IRNSS-1H was itself a replacement satellite for the IRNSS-1A. The three redundant navigation clocks on the IRNSS-1A failed **over a period of three months** . [caption id=“attachment_3998765” align=“alignleft” width=“380”]  The IRNSS-1C undergoing a vibration test. Image: ISRO.[/caption] According to a report in The Hindu, ISRO has started assembling the replacement IRNSS-1I satellite. The satellite had already been approved as an emergency replacement in case one of the satellites in India’s navigation constellation failed. India’s navigation constellation requires seven satellites in orbit, and two on the ground as emergency replacements in case of the failure of one of the seven. ISRO plans to increase the number of navigation satellites in orbit from seven to eleven, but currently seven satellites in orbit, and two backup satellites have been approved. If the space agency has to come up with the IRNSS-1J, it will probably do so with the participation of private industries. The IRNSS-1H was supposed to be the first satellite that ISRO had launched after partnering with private companies. On 31 August, 2017, **ISRO's PSLV-C39** mission failed to deploy the IRNSS-1H satellite. The satellite was housed in the conical portion right on top of the rocket, known as the heat shield or the payload fairing. The heat shield field to separate at the last moment, trapping the satellite within it. Low tech **explosive elements** are believed to be the cause of the lack of separation, and the results from a **thorough investigation** by ISRO are awaited. The satellite enclosed within the heat shield is expected to **burn up in the atmosphere** in October or November this year. Each satellite in the constellation is expected to run for 10 to 12 years. Each satellite in the Indian regional navigation satellite system (IRNSS) constellation costs Rs 150 crore, and the PSLV launch in the XL configuration costs about Rs 130 crore. Together, the constellation will provide navigation and geolocation services across India. This can be used by smartphones, road vehicles, aircraft and vessels in the sea. The constellation will also support geofencing applications, monitor sea vessels straying too close to international borders, and provide support for logistics companies. [caption id=“attachment_3999993” align=“aligncenter” width=“825”]  Apparently the IRNSS architecture includes a laser.[/caption] ISRO is **preparing for its next PSLV flight some time**  in November or December, and the exact details of the mission are not known yet. Towards the very end of the year, on 28 December, two contenders for Google’s Lunar XPRIZE, India’s Team Indus and Japan’s Team Hakuto will rideshare on a PSLV in an attempt to be the **private company to land a rover on the Moon** .