India-France Space Cooperation (ISRO-CNES)

India and France have one of the oldest and closest space partnerships in the world. India's space agency ISRO and France's space agency CNES (Centre national d'études spatiales) have worked together for over 60 years. They have shared rocket technology, launched Indian satellites on French rockets and built joint satellites. Today they cooperate on Earth observation, human spaceflight, and space start-ups.

Why does this partnership matter?

For India, France was an early partner that shared technology when many countries would not. For France, India offers skilled engineers, low-cost launches and a huge market. Both countries also want "strategic autonomy", which means not depending too much on any one big power. Space cooperation fits this shared goal.

Where did it come from?

The link began in the 1960s. French Centaure sounding rockets were launched from the Thumba Equatorial Rocket Launching Station near Thiruvananthapuram. A sounding rocket is a small rocket that goes up, takes measurements of the upper atmosphere and falls back. It does not go into orbit. These early launches helped Indian scientists learn rocket building.

The Vikas engine story

In 1974, ISRO signed an agreement with the French company SEP (Société Européenne de Propulsion). France gave India liquid rocket engine technology. In return, Indian engineers gave about 100 man-years of work to France's Ariane rocket programme. From this came India's Vikas engine, based on the French Viking engine. Vikas later powered the second stage of the PSLV and stages of the GSLV. So a large part of India's rocket success rests on this deal.

Launching Indian satellites

In 1981, India's first experimental communication satellite APPLE (Ariane Passenger Payload Experiment) was launched on a French Ariane rocket. Since then, many Indian communication satellites of the INSAT and GSAT series have gone up on Ariane rockets from Kourou in French Guiana.

The joint satellites

After a broad agreement in 2008, ISRO and CNES built two satellites as equal partners:

1. Megha-Tropiques (2011): Launched on 12 October 2011 by PSLV-C18. It studied the water cycle and energy balance of the tropical atmosphere: rain, clouds and humidity. Its instruments included MADRAS (built jointly), SAPHIR and ScaRaB (built by CNES). ISRO brought it down in a controlled re-entry on 7 March 2023, so it would not become space junk.
2. SARAL (2013): The Satellite with ARgos and ALtiKa was launched on 25 February 2013 by PSLV-C20. Its main instrument, AltiKa, is a radar altimeter working in the Ka band. It measures the height of the sea surface, which helps study ocean currents, sea-level rise and weather. The ARGOS system collects data from buoys and tags on animals.
3. TRISHNA (planned 2027): The third joint satellite, for high-resolution thermal imaging of land and water. Its full name is Thermal infraRed Imaging Satellite for High-resolution Natural resource Assessment. It measures how hot the land and water surface is. This shows how much water crops and forests are losing, so it helps plan irrigation and track droughts and city heat. The work is split. CNES builds the thermal infrared instrument, the main camera. ISRO builds the satellite body and a second camera that sees visible and near-infrared light, and launches it on a PSLV. It will fly in a sun-synchronous orbit about 761 km high and see each place roughly every 3 days, at about 60 m detail. As of October 2026, the launch is planned for 2027.

Human spaceflight

France helps India's Gaganyaan programme. Under an agreement announced in April 2021, CNES trained Indian flight physicians (doctors who look after astronauts) and mission control teams in France. France also supplies some equipment and consumables for the mission.

The bigger framework

India and France became strategic partners in 1998. Space was one of the first pillars of that partnership. In July 2023, both countries adopted the Horizon 2047 roadmap. It guides the relationship until 2047, when India completes 100 years of independence and the partnership completes 50 years. Space is a key area in this roadmap. CNES also has an office in Bengaluru, and India is one of CNES's largest partners after the US space agency NASA.

Commonly confused concepts

• ISRO vs CNES vs ESA: ISRO is India's space agency. CNES is France's national space agency. ESA (European Space Agency) is a group of European countries, including France, working together.
• Megha-Tropiques vs SARAL: Megha-Tropiques studied the atmosphere (rain, clouds, humidity). SARAL studies the ocean surface (sea height).
• Vikas vs Viking: Viking is the French engine used on early Ariane rockets. Vikas is India's version, made after the 1974 technology deal.
• Sounding rocket vs launch vehicle: A sounding rocket goes up and falls back. A launch vehicle like PSLV puts satellites into orbit.

Issues, criticism and the way forward

• Delays: Joint missions take a long time because two agencies must match designs, budgets and schedules. TRISHNA was first discussed years ago and is only now reaching launch stage.
• Competition: India's low-cost launchers compete with Europe's Ariane rockets for commercial satellites, which can create tension alongside cooperation.
• Space debris and security: Both countries now also work on space situational awareness (tracking objects in orbit) and responsible behaviour in space.
• Way forward: Both sides plan to widen cooperation to start-ups (India has over 400 space start-ups), human spaceflight, microgravity research and reusable rockets.

Concepts to Know

• Earth observation satellite: A satellite that takes pictures or measurements of Earth, used for weather, farming, water and disaster planning.
• Radar altimeter: An instrument that sends radio pulses down and times their echo to measure height, for example of the sea surface.
• Thermal infrared imaging: Taking pictures of the heat that objects give off, instead of the light they reflect. A dry, stressed field looks hotter than a well-watered one.
• Sun-synchronous orbit: An orbit over the poles in which the satellite passes over each place at the same local time every day, so pictures can be compared fairly.
• Controlled re-entry: Bringing an old satellite down in a planned way so it burns up or falls in an empty ocean area.
• Strategic autonomy: A country's freedom to make its own choices in foreign and defence policy without being tied to one power.