IRNSS-1I is the eighth satellite in the Indian Regional Navigational Satellite System (IRNSS) series of satellites, in reality, IRNSS - 1I is the ninth satellite that launched in IRNSS constellation but it is counting as eighth satellite because IRNSS - 1I is an eighth satellite that has launched successfully in IRNSS constellation.[6] ISRO already launched IRNSS-1A, IRNSS-1B, IRNSS-1C, IRNSS-1D, IRNSS-1E, IRNSS-1F, IRNSS-1G and IRNSS-1H. The satellite is intended to replace the failed IRNSS-1A, and complete the constellation of geosynchronous navigation satellites after IRNSS-1H failed to do so. The satellite's assembly, integration and testing is partly done by a consortium of six small firms led by Alpha Design Technologies, a Bengaluru-based aerospace firm under URSC's supervision.[7]

IRNSS Series 1.jpg
IRNSS series one spacecraft
Mission typeNavigation
COSPAR ID2018-035A[1]
SATCAT no.43286[2]
Mission duration10 years
Spacecraft properties
ManufacturerISRO Satellite Centre
Space Applications Centre
Launch mass1,425 kilograms (3,142 lb)
Dry mass600 kilograms (1,300 lb)
Start of mission
Launch date11 April 2018, 22:34 UTC[3]
RocketPSLV-XL C41 [4]
Launch siteSatish Dhawan SLP
Orbital parameters
Reference systemGeocentric
Longitude55° E
Period1450.9 minutes[5]


Like its predecessor, IRNSS-1I has two types of payloads, navigation payload and the ranging payload. The navigation payload transmits navigation service signals to the users. This payload is operating in L5 band and S band. A highly accurate Rubidium atomic clock is part of the navigation payload of the satellite.[8] Failure of these Rubidium atomic clocks was the reason for IRNSS-1A to be deemed unfit. The ranging payload consists of transponder which is operated in CDMA mode for two-way range measurements. The IRNSS satellites continuously emits time stamped navigation signals, which are received by the ground-based user receivers. The information is then processed by the receivers to derive their own position, velocity and time. The system provides seamless, uninterrupted services under all weather conditions.


The satellite will help in completing the satellite based navigation system of India which is currently under development. The IRNSS space segment consists of seven satellites. After the failure of all three Rubidium Atomic clocks on-board IRNSS-1A and the failure of IRNSS-1H to separate from the heat shield of the launch vehicle, IRNSS constellation remains incomplete without this satellite.
This independent regional navigation satellite system is developed by India and is similar to Global Positioning System (GPS) of the US, which has 31 satellites currently in orbit.


IRNSS-1I was successfully launched by 43rd flight of PSLV (PSLV-C41) in XL configuration on 11 April 2018.[9][10]

Animation of IRNSS
Around the Earth
Around the Earth - Polar view
Earth fixed frame - Equatorial view, front
Earth fixed frame - Equatorial view, side
Earth fixed frame - Polar view
   Earth ·   IRNSS-1B  ·   IRNSS-1C  ·   IRNSS-1E  ·   IRNSS-1F  ·   IRNSS-1G  ·   IRNSS-1I

See alsoEdit


  1. ^ "IRNSS 1I Satellite details". n2yo. Retrieved 14 April 2018.
  2. ^ "IRNSS 1I". karhukoti. Retrieved 19 April 2018.
  3. ^ "Launch date". Spaceflight101. 27 March 2018.
  4. ^ "Official page". Economic Times. 11 March 2018. Archived from the original on 17 March 2018. Retrieved 16 March 2018.
  5. ^ "IRNSS 1I". karhukoti. Retrieved 19 April 2018.
  6. ^ "ISRO Successfully Launched IRNSS - 1I Navigation Satellite By PSLV - C41". EDUCATIONALTECHS , edited by -Vikash Kushwaha. Retrieved 17 April 2018.
  7. ^ "Industry partnership with Alpha Design Technologies". The Hindu. 14 August 2017.
  8. ^ "ISAC's website for IRNSS". ISAC. 31 August 2017.
  9. ^ "IRNSS-1I up in space, completes first phase of Indian regional navigation constellation".
  10. ^ "Isro successfully launches navigation satellite IRNSS-1I to replace faulty IRNSS-1A".

External linksEdit