ISRO’s GISAT-1A (EOS-05): India’s Geo-Imaging Satellite for Near Real-Time Monitoring
ISRO is preparing for the launch of GISAT-1A, also referred to as EOS-05, a next-generation geo-imaging satellite designed to significantly strengthen India’s capability for near real-time observation of the Indian subcontinent.
For UPSC aspirants, this development is important under:
- GS-III (Science & Technology, Disaster Management, Internal Security)
- Prelims (Space missions, Earth observation satellites, ISRO launch vehicles)
Unlike conventional Earth Observation (EO) satellites that move in sun-synchronous polar orbits and revisit the same location after days, GISAT-1A will operate from a geostationary orbit and will be capable of imaging the same region repeatedly within minutes.
What is GISAT-1A (EOS-05)?
GISAT stands for Geo Imaging Satellite. It is a dedicated Earth observation platform planned to operate from Geostationary Orbit (GEO) at approximately 36,000 km above Earth.
Key Idea
Instead of “passing over” India like polar satellites, GISAT-1A will remain fixed over the same region (relative to Earth) and continuously observe the subcontinent.
This makes it ideal for:
- Cyclone tracking
- Flood monitoring
- Forest fire detection
- Cloud movement analysis
- Rapid border-area observation
Launch Schedule and Mission Details
ISRO has issued a Notice to Airmen (NOTAM) indicating a launch window between:
📌 20 February 2026 and 05 March 2026
Launch Vehicle
The satellite will be launched using:
- GSLV-F17 (GSLV Mk II)
Launch Site
- Second Launch Pad, Satish Dhawan Space Centre (SDSC), Sriharikota
Why GSLV?
A geostationary satellite requires a powerful launcher because:
- It must be placed into the Geosynchronous Transfer Orbit (GTO)
- Then it uses onboard propulsion to reach the final GEO
GSLV Mk II is India’s operational workhorse for such missions.
Why GISAT-1A is Significant for India?
1) Near Real-Time Imaging of the Subcontinent
One of the biggest advantages of a GEO imaging satellite is its ability to provide:
- Full-disk images of India every ~30 minutes
- Sector-based images every ~5 minutes (for selected areas)
This is a major leap compared to conventional EO satellites, where:
- Imaging depends on the orbit pass timing
- Revisit periods can be 2–5 days
Such rapid observation is critical for:
- Cyclones
- Landslides
- Flash floods
- Large-scale forest fires
- Major infrastructure disasters
2) Strengthening India’s Disaster Management Architecture
India is one of the world’s most disaster-prone countries due to:
- Long coastline (cyclones)
- Himalayan region (landslides)
- River systems (floods)
- Heatwaves and droughts
GISAT-1A can provide continuous imagery for:
- Early warning
- Real-time response coordination
- Damage assessment
This improves the efficiency of:
- NDMA
- IMD
- NDRF
- State Disaster Management Authorities
3) Agriculture, Forestry and Water Resource Monitoring
The satellite is equipped with advanced sensors that allow:
- Crop health monitoring
- Soil moisture and drought stress observation
- Vegetation index mapping
- Forest cover change detection
This data supports:
- Precision agriculture
- Crop insurance
- Food security planning
- Climate resilience
4) Strategic Utility for National Security
Although GISAT-1A is primarily designed for civilian applications, it carries high strategic relevance.
Its ability to repeatedly image the same region makes it valuable for:
- Border surveillance
- Monitoring of sensitive sectors
- Persistent watch during emergencies
In modern security environments, persistent intelligence is often more useful than one-time high-resolution snapshots.
Advanced Payload and Technology on GISAT-1A
GISAT-1A is expected to carry multi-spectral and hyper-spectral imaging instruments, enabling it to detect a wide range of surface features.
Imaging Bands
The satellite payload covers:
- Visible and Near Infrared (VNIR)
- Short Wave Infrared (SWIR)
Why VNIR and SWIR matter?
These bands help in:
- Vegetation and crop monitoring
- Mineral and soil analysis
- Water body mapping
- Disaster assessment
Telescope System
The mission includes an advanced optical system such as:
- 700 mm Ritchey–Chrétien telescope
This design is widely used in high-performance space telescopes because it:
- Reduces optical aberrations
- Improves image clarity across the field
GISAT-1A vs GISAT-1 (EOS-03): Background
GISAT-1A is also significant because it is effectively a replacement for GISAT-1 (EOS-03).
What happened to EOS-03?
- EOS-03 was launched in August 2021
- The mission failed due to a technical anomaly in the cryogenic upper stage of the launch vehicle
- The satellite could not be placed into its intended orbit
The loss of EOS-03 delayed India’s plan for a dedicated geo-imaging satellite.
GISAT-1A aims to restore and strengthen this capability.
What is NOTAM and Why is it Issued?
A Notice to Airmen (NOTAM) is an official aviation advisory issued to:
- Inform aircraft operators about restricted zones
- Warn about launch trajectories
- Prevent civilian flights from entering dangerous areas during launch
For UPSC Prelims, NOTAM is an important term often used in:
- Space launches
- Missile tests
- Defence drills
Why is Geostationary Orbit is Important for GISAT Missions?
Geostationary Orbit (GEO)
- Altitude: ~36,000 km
- Satellite appears fixed over the same location
Key Advantage
- Continuous observation of the same region
Limitation
- Generally lower spatial resolution compared to polar orbit satellites (because GEO is much farther)
However, GISAT-1A focuses on:
- High temporal resolution (fast repeat imaging)
This makes it ideal for dynamic events.
Relevance for UPSC Prelims and Mains
Prelims Pointers
- GISAT stands for Geo Imaging Satellite
- EOS-05 is the alternate name of GISAT-1A
- Launch vehicle: GSLV Mk II
- Orbit: Geostationary
- Revisit time: 5 minutes for selected sectors
Mains GS-III Themes
- Role of space technology in disaster management
- Earth observation and climate resilience
- Dual-use technologies in internal security
- Indigenous capability in cryogenic engine missions
Conclusion
The launch of GISAT-1A (EOS-05) represents an important step in India’s Earth observation journey. With its ability to provide near real-time monitoring, the satellite will significantly enhance India’s preparedness for natural disasters, strengthen agriculture and resource planning, and indirectly contribute to national security through persistent surveillance.
For UPSC aspirants, GISAT-1A is not just a science-and-technology update but also a high-value topic connecting disaster management, governance, internal security, and climate resilience.
FAQs
Q1. What is GISAT-1A (EOS-05)?
GISAT-1A, also known as EOS-05, is ISRO’s geo-imaging satellite designed to provide near real-time observation of the Indian subcontinent from geostationary orbit.
Q2. What is the orbit of GISAT-1A?
GISAT-1A will operate from geostationary orbit at around 36,000 km above Earth.
Q3. Which launch vehicle will carry GISAT-1A?
GISAT-1A is planned to be launched using GSLV-F17 (GSLV Mk II).
Q4. How is GISAT different from other Earth observation satellites?
Most EO satellites operate in polar sun-synchronous orbits and revisit the same area after days. GISAT stays fixed over the same region in geostationary orbit and can image repeatedly within minutes.
Q5. How frequently can GISAT-1A capture images?
It can capture images of the entire Indian landmass roughly every 30 minutes and selected sectors every 5 minutes.
Q6. Why is GISAT important for disaster management?
Its high temporal resolution enables continuous tracking of cyclones, floods, forest fires and other fast-changing disasters, improving early warning and response.
Q7. What was EOS-03 and why is GISAT-1A being launched?
EOS-03 (GISAT-1) was a similar satellite launched in August 2021 but was lost due to a cryogenic stage anomaly. GISAT-1A is planned as its replacement.
Q8. What is NOTAM in the context of space launches?
NOTAM (Notice to Airmen) is an aviation advisory that restricts airspace near a launch corridor to ensure flight safety.
