In a historic milestone, the Indian Space Research Organisation (ISRO) is set to launch its 100th mission today. The Geosynchronous Satellite Launch Vehicle (GSLV-F15) is scheduled for lift-off at 6:23 AM from the Satish Dhawan Space Centre (SDSC), Sriharikota, carrying the NVS-02 navigation satellite into geosynchronous transfer orbit.
This mission is ISRO’s 17th GSLV flight and the 11th to feature an indigenous cryogenic upper stage. Additionally, it marks the first space launch under ISRO’s new chairman, V. Narayanan, who took charge on 13 January 2025.
What is NVS-02 and Why is it Important?
The NVS-02 satellite is part of India’s Navigation with Indian Constellation (NavIC) system, which provides precise Position, Velocity, and Timing (PVT) services to users in India and surrounding regions up to 1,500 km beyond the country’s borders.
The satellite is designed to enhance navigation services across multiple sectors, including transportation, agriculture, emergency response, fleet management, and mobile location-based services.
NVS-02 is the second in the new-generation NVS satellite series, following the launch of NVS-01 on 29 May 2023. Like its predecessor, it is equipped with navigation payloads in L1, L5, and S bands, along with a ranging payload in the C-band. Notably, NVS-02 incorporates both indigenous and procured atomic clocks, crucial for precise time estimation.
Key Specifications of NVS-02
- Weight: ~2,250 kg
- Platform: Standard I-2K bus
- Power Handling Capability: ~3 kW
- Orbital Position: 111.75°E, replacing IRNSS-1E
- Payload Features: Tri-band navigation system with atomic frequency standards
GSLV-F15: A Closer Look at the Rocket
The GSLV-F15 is a three-stage rocket, designed to deploy satellites into geosynchronous transfer orbit (GTO). It consists of:
- First Stage (GS1): S139 solid rocket motor + four L40H liquid strap-on boosters
- Second Stage (GS2): GL40HT liquid engine
- Third Stage (GS3): Indigenous cryogenic engine (CUS15)
GSLV-F15 Quick Stats:
- Vehicle Height: 50.9 metres
- Lift-off Mass: 420.7 tonnes
- Payload Fairing Diameter: 3.4 metres
- Target Orbit: 170 km perigee, 36,577 km apogee
- Estimated Separation Time of NVS-02: ~1,150 seconds after lift-off
NVS-02: Development and Testing
The NVS-02 satellite was designed and integrated at UR Rao Satellite Centre (URSC), Bengaluru, with contributions from multiple ISRO work centres. The satellite underwent rigorous pre-launch tests, including:
- Thermo-vacuum testing (Nov-Dec 2024) – Simulating space conditions
- Dynamic testing (Dec 2024) – Ensuring structural integrity
- Acoustic and vibration tests – Confirming resilience to launch conditions
Following a Pre-Shipment Review (PSR) on 27 December 2024, NVS-02 was transported to Sriharikota on 5 January 2025 for final integration ahead of today’s scheduled launch.
QUICK FACTS: ISRO’s 100th Mission & GSLV-F15
| Feature | Details |
|---|---|
| Mission | ISRO’s 100th space launch |
| Rocket | GSLV-F15 (17th GSLV flight, 11th with cryogenic upper stage) |
| Launch Time | 6:23 AM IST, 29 Jan 2025 |
| Launch Site | Satish Dhawan Space Centre, Sriharikota |
| Payload | NVS-02 Navigation Satellite (~2,250 kg) |
| Target Orbit | Geosynchronous Transfer Orbit (GTO) |
| Chairman of ISRO | V. Narayanan (First mission under his leadership) |
| Primary Use | Navigation, positioning, and timing services for India & nearby regions |
| Orbital Position | 111.75°E, replacing IRNSS-1E |
Why This Mission Matters
Strengthening India’s Navigation Capabilities – NVS-02 is part of the second-generation NavIC system, improving GPS-independent navigation for India.
Boosting Indigenous Space Technology – Features atomic clocks, essential for precise timing applications in communication, defence, and space research.
Enhancing Global Positioning Services – The L1 band addition makes NavIC-compatible devices more accessible for commercial and consumer applications.
ISRO’s 100th Launch Milestone – A significant achievement in India’s space journey, reflecting decades of progress in satellite technology and launch vehicle development.
Final Countdown Underway
As ISRO prepares for the historic launch, all eyes are on Sriharikota. The mission’s success will further solidify India’s position as a global space power, ensuring self-reliant satellite navigation and reducing dependence on foreign GPS services.
(All images courtesy – ISRO website)
