# IRNSS-1I

> Indian navigation satellite

**Wikidata**: [Q25428047](https://www.wikidata.org/wiki/Q25428047)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/IRNSS-1I)  
**Source**: https://4ort.xyz/entity/irnss-1i

## Summary
IRNSS-1I is an Indian navigation satellite launched on April 11, 2018, as part of the Navigation with Indian Constellation (NavIC) system. It was designed to replace the failed IRNSS-1A and enhance regional positioning services over India and neighboring regions. The satellite operates in a geostationary orbit and was developed by the Indian Space Research Organisation (ISRO).

## Key Facts
- Launched on April 11, 2018, at 22:34 UTC from the Satish Dhawan Space Centre First Launch Pad.
- Replaced the failed IRNSS-1A satellite to maintain constellation integrity.
- Part of the Navigation with Indian Constellation (NavIC), India’s indigenous regional navigation system.
- Weighs 1,425 kg at launch and approximately 614 kg dry weight.
- Operates in geostationary orbit under control of ISRO.
- Powered by two spacecraft solar arrays and a liquid apogee engine.
- Built using the I-1K spacecraft bus; manufactured by ISRO.
- COSPAR ID: 2018-035A; SCN: 43286; NSSDCA ID: 2018-035A.
- Launched aboard PSLV-C41, a variant of the Polar Satellite Launch Vehicle-XL.
- Followed by NVS-01, which introduced next-generation capabilities.

## FAQs
### Q: What is IRNSS-1I used for?
A: IRNSS-1I provides accurate positioning and timing services as part of India's NavIC system. It supports civilian and military applications across the Indian region and up to 1,500 km beyond its borders.

### Q: Who built IRNSS-1I?
A: IRNSS-1I was developed and manufactured by the Indian Space Research Organisation (ISRO). It uses ISRO's I-1K spacecraft bus platform.

### Q: When was IRNSS-1I launched?
A: IRNSS-1I was successfully launched on April 11, 2018, at 22:34 UTC from the Satish Dhawan Space Centre in Sriharikota, India.

## Why It Matters
IRNSS-1I plays a critical role in maintaining the operational strength of India’s indigenous regional navigation satellite system, NavIC. Following the failure of IRNSS-1A, IRNSS-1I restored full constellation capability, ensuring uninterrupted service for users relying on precise location data for transportation, disaster management, vehicle tracking, and defense operations. Its successful deployment underscores India’s growing autonomy in space-based navigational infrastructure, reducing dependence on foreign systems like GPS. As part of a broader initiative toward self-reliance in strategic technologies, IRNSS-1I contributes significantly to national security, economic development, and technological sovereignty.

## Notable For
- Replacement of the failed IRNSS-1A, restoring full constellation functionality.
- First Indian navigation satellite launched after a gap due to earlier mission failures.
- Integral component of the operational NavIC system certified for both civilian and military use.
- Demonstrated ISRO’s ability to rapidly rebuild and deploy replacement satellites within two years.
- Utilized the proven PSLV-C41 launcher configuration for reliable orbital insertion.

## Body
### Mission Overview
IRNSS-1I was launched as a replacement for IRNSS-1A, whose onboard atomic clocks had failed, rendering it non-operational. The satellite was essential to maintain the minimum seven-satellite configuration required for the NavIC system to deliver accurate positioning information over India and surrounding areas.

### Technical Specifications
- **Launch Mass**: 1,425 kilograms (including fuel).
- **Dry Mass**: Approximately 614 kilograms.
- **Power System**: Equipped with two deployable solar arrays and one liquid apogee engine for orbital maneuvers.
- **Orbit Type**: Geostationary orbit.
- **Spacecraft Bus**: Based on the I-1K platform developed by ISRO.
- **Manufacturer**: Indian Space Research Organisation (ISRO).

### Launch Details
- **Date**: April 11, 2018
- **Time**: 22:34 UTC
- **Location**: Satish Dhawan Space Centre First Launch Pad, Sriharikota, India
- **Vehicle**: PSLV-C41 (Polar Satellite Launch Vehicle - XL variant)
- **Mission Outcome**: Successful deployment into intended orbit.

### Operational Role
- Integrated into the NavIC system to ensure continuous regional navigation coverage.
- Supports dual-frequency signals for enhanced accuracy and robustness.
- Provides Standard Positioning Service (SPS) for civilians and Restricted Service (RS) for authorized users including the armed forces.

### Succession and Legacy
- Followed directly by IRNSS-1H (which itself preceded IRNSS-1I chronologically but was not functional).
- Succeeded by NVS-01, the first satellite in the upgraded second generation of the Indian navigation system.
- Marked a pivotal moment in sustaining India’s independent satellite navigation program post-initial constellation establishment.

## Schema Markup
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## References

1. [Source](https://www.isro.gov.in/launchers/list-of-pslv-launches)
2. [Source](https://space.skyrocket.de/doc_sdat/irnss.htm)
3. Jonathan's Space Report
4. [Source](https://www.isro.gov.in/spacecraft/list-of-navigation-satellites)