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TRISHNA: India–France Joint Earth Observation Mission
What’s the News?
- ISRO and France’s CNES (Centre National d'Études Spatiales) are jointly developing TRISHNA, an advanced Earth-observation satellite for high-resolution monitoring of land and coastal surface temperatures.
- TRISHNA stands for Thermal infraRed Imaging Satellite for High-resolution Natural resource Assessment.
- The mission will combine thermal-infrared and optical observations to study water stress, agriculture, urban heat, glaciers, coastal waters and climate-related processes.
- The mission is currently under development and is targeted for launch aboard India’s PSLV in 2027. CNES lists delivery of its thermal-infrared instrument to India during 2026.
TRISHNA Mission
| Feature | Details |
|---|---|
| Partners | ISRO, India & CNES, France |
| Mission Type | Earth Observation |
| Planned Launch | 2027 |
| Launch Vehicle | PSLV |
| Orbit | Sun-Synchronous Orbit (SSO) |
| Altitude | 761 km |
| Mission Life | 5 years |
| Equatorial Revisit | About 3 days |
| Product Resolution | About 60 metres |
The satellite is designed to combine high spatial resolution with frequent revisit, allowing environmental changes to be tracked at relatively fine scales several times a week.
Payloads
TRISHNA carries two major observation systems:
- Thermal Infrared (TIR) Payload — CNES
- Developed under the French contribution.
- Contains 4 long-wave thermal-infrared bands.
- Measures:
- Land and water surface temperature
- Surface emissivity
- Thermal variations
- VNIR-SWIR Payload — ISRO
- VNIR: Visible and Near Infrared
- SWIR: Short-Wave Infrared
- Contains 7 spectral bands.
- Measures surface reflectance and generates information on:
- Vegetation
- Biophysical characteristics
- Radiation balance
- Land-surface conditions.
Major Objectives
- Water Stress: Assess water stress in crops and natural vegetation.
- Evapotranspiration: Estimate water lost through evaporation from soil and transpiration from plants.
- Agriculture: Support irrigation planning and efficient water use.
- Urban Heat Islands: Map unusually high temperatures in built-up urban areas.
- Cryosphere: Monitor glaciers, snowmelt and related hydrological processes.
- Coastal & Inland Waters: Study water temperature, quality and dynamics.
- Geological Applications: Identify thermal anomalies associated with volcanic and geothermal activity.
- Climate Studies: Improve understanding of Earth's surface energy and water budgets.
Why Thermal Infrared Observation Matters?
- Objects on Earth's surface emit thermal radiation according to their temperature.
- Thermal infrared sensors can measure this emitted radiation and estimate land or water surface temperatures.
- When thermal data are combined with vegetation and surface-reflectance information, scientists can estimate the surface energy balance and evapotranspiration.
- Such information is particularly useful for:
- Drought assessment
- Irrigation management
- Crop-water requirement estimation
- Heat-wave and urban-heat studies
- Glacier monitoring
Sun-Synchronous Orbit
- TRISHNA will operate in a Sun-Synchronous Orbit (SSO) at about 761 km altitude.
- In an SSO, a satellite generally passes over a given location at nearly the same local solar time.
- This provides comparable illumination and observation conditions, making SSO particularly useful for Earth-observation and environmental-monitoring satellites.
- TRISHNA's planned local equatorial crossing time is around 12:30 PM.
India–France Space Cooperation
- India and France have one of India's oldest international space partnerships.
- ISRO is responsible for:
- Satellite platform
- VNIR-SWIR instrument
- Overall satellite integration
- Indian launch through PSLV
- CNES is responsible for the TIR instrument, developed with French industry.
- Mission data processing will be undertaken through facilities in India and France.
Other Major India–France Space Cooperation
- Megha-Tropiques: Study of tropical atmosphere and climate.
- SARAL: Satellite with ARGOS and ALTIKA for oceanographic studies.
- TRISHNA: High-resolution thermal Earth observation.
- Cooperation also covers areas such as maritime-domain awareness, climate monitoring and space situational activities.
Additional Info
- CNES
- Full name: Centre National d'Études Spatiales
- National space agency of France.
- Headquarters: Paris.
- PSLV
- Full form: Polar Satellite Launch Vehicle.
- Developed by ISRO.
- Widely used to place Earth-observation satellites into polar and Sun-synchronous orbits.
- Current Status
- ISRO's 2025–26 Annual Report states that TRISHNA satellite realisation is progressing, with the Preliminary Design Review (PDR) completed for satellite-bus elements and the VNIR/SWIR payloads.
- Earlier material referred to a 2026 launch, but the current CNES mission schedule lists launch in 2027.