NISAR Satellite Launch

India is set to launch the NASA-ISRO Synthetic Aperture Radar (NISAR) satellite. This mission is a collaboration between NASA and the Indian Space Research Organisation (ISRO). The satellite will be launched aboard the Geosynchronous Satellite Launch Vehicle Mark II (GSLV Mk II). This launch represents advancement in India’s space capabilities.

GSLV Mk II

The GSLV Mk II is a three-stage rocket. It stands at 50.9 metres tall and can carry up to 2,500 kilograms to a Geosynchronous Transfer Orbit (GTO). It can also transport 5,000 kilograms to a Low Earth Orbit (LEO). The rocket consists of a solid-fuel first stage and two liquid-fuel stages. Each stage plays important role in ensuring the satellite reaches its intended orbit.

First Stage – Solid Fuel Motor

The first stage of the GSLV Mk II uses a solid-fuel motor. It is assisted by four liquid-fueled boosters. This combination generates the initial thrust needed to escape Earth’s gravity. Once the first stage burns out, the rocket transitions to the second stage.

Second Stage – GS2 Liquid Propulsion

The GS2 stage is powered by a Vikas engine. This engine uses hypergolic propellants, specifically unsymmetrical dimethylhydrazine (UDMH) and nitrogen tetroxide (N₂O₄). These propellants ignite upon contact, enhancing reliability. The GS2 burns for about 150 seconds, providing controlled thrust. This stage is critical for correcting flight path deviations during ascent.

Third Stage – Cryogenic Propulsion

The third stage, GS3, utilises cryogenic propellants—liquid hydrogen (LH2) and liquid oxygen (LOX). This stage burns for approximately 720 seconds, delivering the final push to position the satellite correctly. The efficiency of cryogenic fuels marks achievement for India in rocket technology.

Interconnected Stages

The performance of each rocket stage is interconnected. A failure in one stage can jeopardise the entire mission. For instance, the GSLV-F10 mission in 2021 faced issues due to a malfunction in the cryogenic stage. This incident brought into light the importance of each stage working harmoniously.

NISAR Satellite Capabilities

The NISAR satellite will orbit Earth at an altitude of 747 km. It will utilise L-band and S-band radars to monitor changes such as deforestation and natural disasters. NISAR will provide high-resolution data every 12 days, enhancing environmental monitoring.

ISRO’s Advancements and Future Missions

ISRO’s successful handling of the GS2 stage showcases its growing expertise in liquid propulsion systems. This capability is crucial for future missions, including human spaceflight (Gaganyaan) and commercial launches through NewSpace India Limited (NSIL). The meticulous preparation reflects ISRO’s commitment to high safety standards and engineering excellence.

Questions for UPSC:

1. Discuss the significance of India’s collaboration with NASA on the NISAR satellite mission.
2. Critically examine the role of liquid propulsion systems in modern space missions.
3. Explain the importance of inter-stage performance in rocket launches. How does it affect mission success?
4. What are the environmental monitoring capabilities of the NISAR satellite? Discuss with suitable examples.

Answer Hints:

1. Discuss the significance of India’s collaboration with NASA on the NISAR satellite mission.

1. Strengthens international partnerships in space exploration.
2. Combines expertise in satellite technology for enhanced capabilities.
3. Facilitates sharing of data and resources for global challenges.
4. Promotes India’s position in the global space industry.
5. Encourages technological advancements and innovation in India.

2. Critically examine the role of liquid propulsion systems in modern space missions.

1. Provides precise control and maneuverability during flight.
2. Allows for adjustments in flight path, enhancing mission success.
3. Utilizes hypergolic propellants for reliable ignition and performance.
4. Supports complex missions requiring high efficiency and reliability.
5. Represents technological advancement in rocket design.

3. Explain the importance of inter-stage performance in rocket launches. How does it affect mission success?

1. Each stage’s performance directly impacts the next stage’s efficiency.
2. A failure in one stage can lead to mission failure or satellite loss.
3. Ensures the rocket reaches the correct altitude and velocity for orbit.
4. Critical for maintaining trajectory and correcting flight deviations.
5. Demonstrates the interconnected nature of rocket engineering and design.

4. What are the environmental monitoring capabilities of the NISAR satellite? Discuss with suitable examples.

1. Monitors deforestation and land-use changes over time.
2. Tracks melting glaciers and climate change impacts.
3. Assesses natural disasters like floods and earthquakes for rapid response.
4. Provides high-resolution data every 12 days for timely analysis.
5. Utilizes dual radar systems for comprehensive Earth observation.