TRISHNA: Indo-French Thermal Satellite for Water Management Nears Launch
An official of ISRO's U.R. Rao Satellite Centre (URSC), Bengaluru, said the Indo-French satellite TRISHNA (Thermal Infra-Red Imaging Satellite for High-resolution Natural Resource Assessment) is in the final building stage and should be launched in the next 12 to 16 months.
TRISHNA is the third joint satellite of India and France, after Megha-Tropiques (2011) and SARAL (Satellite with ARGOS and ALTIKA, 2013).
The work is split: URSC is building the satellite bus (the main body that carries power, control and communication systems) and ISRO's camera, while France's space agency CNES supplies the thermal camera. Data will be processed jointly in both countries.
The satellite will carry two main payloads (instruments): a Thermal Infra-Red (TIR) camera made by CNES and a Visible-Near Infra-Red and Short Wave Infra-Red (VNIR-SWIR) camera made by ISRO.
Its main goal is better management of water resources. It will measure the temperature of land and sea surfaces, which tells us how much water plants and soil are losing.
It will be launched on ISRO's Polar Satellite Launch Vehicle (PSLV), and its science data will follow an open data policy, meaning it will be shared freely with the whole world.
Thermal Infrared Remote Sensing
Every warm object gives off invisible heat rays called thermal infrared radiation. Thermal infrared remote sensing means using cameras on satellites to measure these heat rays from far away, and then working out how hot the land, water or crops below are. It is like a doctor's forehead thermometer, but pointed at the whole Earth from space.
TRISHNA is a thermal infrared mission. By pairing a sharp picture (57 m) with frequent visits (every few days), it aims to track water use by crops, droughts, urban heat and coastal waters in a way older thermal satellites could not, which is why its main goal is described as water management.
India-France Space Cooperation (ISRO-CNES)
India and France have one of the oldest space partnerships in the world. India's space agency ISRO and France's space agency CNES have worked together since the 1960s, on rockets, satellites and now human spaceflight. TRISHNA is the newest joint satellite in this long relationship.
The URSC update shows the third joint Indo-French satellite moving from design to building, with a clear split of work and joint data processing. It adds a climate and water dimension to a partnership that started with rockets.
Polar Satellite Launch Vehicle (PSLV)
The Polar Satellite Launch Vehicle (PSLV) is a rocket made by the Indian Space Research Organisation (ISRO). Its main job is to carry satellites weighing up to about one and a half tonnes into orbits a few hundred kilometres above the Earth, especially orbits that pass over the North and South Poles. Because it has flown so many missions so reliably, it is often called ISRO's "workhorse". TRISHNA, Chandrayaan-1, the Mars Orbiter Mission and Aditya-L1 all went to space on a PSLV.
TRISHNA will be launched on a PSLV, just like the two earlier Indo-French satellites, Megha-Tropiques and SARAL. Its planned 761 km sun-synchronous orbit is exactly the kind of orbit PSLV was built for.
- TRISHNA full form: Thermal Infra-Red Imaging Satellite for High-resolution Natural Resource Assessment
- Partners: ISRO (India) and CNES (France); third joint satellite after Megha-Tropiques (2011) and SARAL (2013)
- Expected launch: in 12 to 16 months from October 2026, on a PSLV
- Payloads: Thermal Infra-Red (TIR, by CNES) and VNIR-SWIR (by ISRO)
- ISRO's role: satellite bus, VNIR-SWIR payload and launch; built at U.R. Rao Satellite Centre, Bengaluru
- Orbit: sun-synchronous, about 761 km; resolution about 57 m over land, 1 km over oceans; revisit about 3 days
- Main aim: water resource management, measuring land surface temperature and evapotranspiration
- Data: open data policy, shared globally