Why in news?

Indian space start-up GalaxEye launched its first satellite 'Drishti' aboard a SpaceX Falcon 9 rocket from Vandenberg Space Force Base, California, as one of 45 payloads on the CAS500-2 mission.

Founded by IIT Madras alumni, GalaxEye has created the world's first satellite capable of capturing optical and radar images simultaneously of the same location — a technological first in space imaging.

What’s in Today’s Article?

• Space imaging
• Limitations of Existing Imaging Technologies
• What Makes Drishti Unique — The Opto-SAR Technology
• Why This Problem is Particularly Indian?
• Applications of Drishti
• India's Growing Space Start-up Ecosystem

Space Imaging

• Space imaging refers to the collection of visual and electromagnetic data from space, used to map celestial bodies, track cosmic phenomena, and monitor Earth's environment.
• This technology translates data from across the electromagnetic spectrum into high-resolution imagery.
• Key Technologies
  • Optical Sensors: Capture visible light to produce detailed, high-resolution photographs of Earth and deep-space objects.
  • Synthetic Aperture Radar (SAR): Emits microwave pulses to map terrain. Because it doesn't rely on sunlight, it can image through clouds, smoke, and total darkness.
  • Infrared and Thermal Imaging: Detects heat signatures, which is essential for studying star formation in deep space and monitoring wildfires or climate patterns on Earth.
  • Hyperspectral Imaging: Breaks down light into hundreds of narrow bands, allowing scientists to identify the exact chemical composition of minerals, vegetation, and gases.
  • AI and Cloud Computing: Modern space systems utilize artificial intelligence directly on orbit to process petabytes of imagery instantly, enabling real-time change detection and analysis.

Limitations of Existing Imaging Technologies

• Space imaging satellites currently use one of two technologies:
  • Optical/Multi-spectral Imaging — Works like a normal camera, producing clear, intuitive, and easy-to-understand images.
    • However, it is ineffective during cloudy weather or night time — a significant limitation for tropical countries like India where cloud cover is frequent and unpredictable.
  • Synthetic Aperture Radar (SAR) — Uses radar signals that can penetrate clouds and capture images continuously regardless of weather or lighting conditions.
    • However, SAR images are not intuitive — like X-ray images, they require trained experts to interpret the data, limiting their usability for general users.
• The Gap — Why Fusion is Needed but Difficult?
  • Users currently need data from multiple satellites — optical data for clarity and SAR data for continuity and all-weather availability.
  • While superimposing these two datasets often works, it has serious limitations.
  • The two satellites are not watching the same place at the same time, and the angles at which they observe Earth can be very different — making accurate data fusion a persistent challenge.

What Makes Drishti Unique — The Opto-SAR Technology?

• Drishti is the world's first satellite equipped with both optical and SAR sensors operating simultaneously to capture images of the same location at the same time.
• GalaxEye calls this proprietary innovation "Opto-SAR technology."
• The Core Technological Challenge — and How It Was Solved
  • SAR and optical sensors are designed differently and look at Earth at different angles.
  • If placed side by side without synchronisation, the optical sensor might be capturing Bengaluru while the SAR sensor is simultaneously capturing Dubai.
  • GalaxEye developed a proprietary technology stack that synchronises the functionalities of both sensors, enabling them to look at the exact same location at the same time.
  • Hence, it eliminates the need for users to manually align datasets from two different satellites.
• The AI Dimension
  • When optical sensors are unable to capture images due to clouds, Drishti uses Artificial Intelligence to regenerate optical-like images from SAR data — further bridging the gap between clarity and all-weather reliability.

Why This Problem is Particularly Indian?

• Most traditional satellite companies are based in Western countries where weather is relatively more predictable and skies are cleaner.
• They do not face the same intensity of cloud cover challenges that countries like India — located in the tropics — routinely experience.
• GalaxEye is therefore solving a problem specific to India and the developing world — making space imagery available all the time and understandable to all kinds of users.

Applications of Drishti

• The data produced by Drishti has both civilian and military applications including:
  • agriculture monitoring,
  • disaster management,
  • urban planning,
  • infrastructure monitoring,
  • border surveillance, and
  • defence intelligence.

India's Growing Space Start-up Ecosystem

• GalaxEye is part of a rapidly emerging wave of Indian private space companies making significant technological contributions.
• Other notable start-ups include:
  • Agnikul Cosmos (IIT Madras) — which built the world's first 3D-printed rocket engine, Skyroot — which tested India's first privately built rocket, and
  • Pixxel, Dhruva Space, and Bellatrix — demonstrating impressive innovations in satellite technologies.
• This ecosystem has been significantly enabled by India's Space Policy 2023, which opened end-to-end space activities to private players.