IRNSS-1I was launched by PSLV-C41 on Thursday early morning, April 12, at 04:04am (IST) from SDSC SHAR, Sriharikota. IRNSS-1I is expected to replace IRNSS-1A.
The Indian Space Research Organisation (ISRO) early on Thursday launched the IRNSS-1I navigation satellite, the eighth such satellite to be a part of a constellation, from Sriharikota in Andhra Pradesh. The PSLV-C41/IRNSS-1I mission blasted off at 4:04 am IST from the first launchpad at the Sathish Dhawan Space Centre and it was a normal lift-off. IRNSS-1I is expected to replace IRNSS-1A, the first of the seven navigation satellites, that was rendered ineffective after its three rubidium atomic clocks failed. The seven satellites are part of the NavIC navigation satellite constellation.
The launch is ISRO’s second attempt at sending a replacement satellite. The previous mission of a PSLV carrying IRNSS-1H in August last year failed after the heat shield covering the satellite failed to separate. The IRNSS-1I mission takes place two weeks after the space agency launched GSAT-6A on board GSLV Mk-II. Though the rocket placed GSAT-6A in orbit, the ISRO lost communication with the satellite within two days. The IRNSS-1I is the eighth navigation satellite to join the IRNSS space segment.
The IRNSS-1I predecessors include IRNSS-1A, 1B, 1C, 1D, 1E, 1F and 1G were launched by PSLV-C22, PSLV-C24, PSLV-C26, PSLV-C27, PSLV-C31, PSLV-C32 and PSLV-C33 in July 2013, April 2014, October 2014, March 2015, January 2016, March 2016 and April 2016 respectively. Like all other IRNSS satellites, IRNSS-1I also has a lift-off mass of 1425 kg. The configuration of IRNSS-1I is similar to IRNSS-1A, 1B, 1C, 1D, 1E, 1F and 1G.
Also read: ISRO IRNSS-1A navigation satellite to launch: Everything you should know
Much like other IRNSS predecessors, IRNSS-1I also carries two types of payloads – a navigation payload and ranging payload. The navigation payload of IRNSS-1I transmits signals for the determination of position, velocity and time. This payload is operating in L5-band and S-band. Rubidium atomic clocks are part of the navigation payload of the satellite. The ranging payload of IRNSS-1I consists of a C-band transponder, which facilitates accurate determination of the range of the satellite. It also carries Corner Cube Retro Reflectors for LASER Ranging.