ISRO's 100th launch: Know all about GSLV-F15's mission and its satellite NVS-02

As India prepares to write another chapter in space exploration this year, January 29 will mark a milestone for India’s premier space agency, Indian Space Research Organisation (ISRO).

For on this day, the GSLV Mk-II will be launched as ISRO's 100th launch vehicle.

This mission, named as the GSLV-F15/NVS-02, is scheduled for a historic launch on January 29, at 6.23 am from the Satish Dhawan Space Centre in Sriharikota. The payload on board is the IRNSS-1K satellite, which is part of India’s regional navigation satellite system.

The mission's objectives

The objective of the GSLV-F15 with indigenous cryogenic stage is to place NVS-02 satellite into a geosynchronous transfer orbit. The NVS-02 is part of India's Navigation with Indian Constellation (NavIC) system, which aims to enhance regional navigation capabilities by providing accurate positioning data over India and neigbouring regions for civilian and military applications. This will help to reduce reliance on foreign systems like GPS.

GSLV-F15 is the 17th flight of India’s Geosynchronous Satellite Launch Vehicle (GSLV) and 11th flight with Indigenous Cryo stage. It is the 8th operational flight of GSLV with an indigenous cryogenic stage.

Also read: Countdown for ISRO's historic 100th mission begins at Sriharikota

What is India's regional navigation satellite system?

The navigation satellite, Navigation with Indian Constellation (NavIC), is India’s independent regional navigation satellite system. It is the second in the NavIC series and is designed to provide precise position, velocity, and time (PVT) services to users in India and the region extending up to approximately 1,500 km beyond the Indian land mass.

The first second-generation satellite, NVS-01, was launched on May 29, 2023, onboard GSLV-F12. Notably, it carried an indigenously developed atomic clock. NVS-02, however, the second satellite in this series, is equipped with navigation payloads operating on L1, L5, and S bands.

What does NavIC Do?

NavIC provides two types of services: Standard Positioning Service (SPS) for general users, similar to GPS and restricted service (RS) for authorised users. The SPS ensures a positional accuracy of better than 20 meters and time accuracy of better than 40 nanoseconds within the service area.

Similar to the GPS of the United States, India's NavIC also has dual usage for the public and the military. NavIC was previously named IRNSS, or India's Navigation Satellite System, which had a much smaller coverage area.

Satellite's applications

So, what are the applications of the satellite on board GSLV-F15? They are:

Land, aerial, and maritime navigation

Precision agriculture

Geospatial studies, emergency services, and naval management

Location-based services for mobile devices

Orbit determination for satellites and marine fisheries

Time services for financial institutions, power grids, and other government operations

Internet of Things (IoT)-based applications

What is NVS-02?

NVS-02, as the name suggests, is the second satellite in the second-generation navigation satellite series and the ninth satellite in the NavIC. Like its predecessor, NVS-01, NVS-02 primarily includes two types of payloads: a navigation payload and a ranging payload. The navigation payload transmits signals to users on earth using three frequency bands in the spectrum: L1, L5, and S-band.

Since time is a critical factor and can be influenced by various elements, the payload includes a Rubidium Atomic Clock to ensure precise timekeeping.

The Rubidium Atomic Clock measures the length of a second by counting the oscillations of Rubidium-87 atoms.

These clocks are highly accurate, with a precision of about three parts in 10 quadrillion. This means they deviate by only one second over 100 million years.

The ranking satellite has a transponder and it helps transmit time-stamped navigation signals to receivers at the ground station. This information is processed at the end-user level to obtain its accurate position, speed, and time. It provides uninterrupted and continuous service, unaffected by earth's weather conditions such as heavy rain, storms, and extreme heat.

The second-generation satellites in NavIC have a strong encryption system (QR code) to keep all communication completely secure.

Also read: ISRO to conduct 100th launch from Sriharikota on Jan 29

India on track to become 5th Global Navigation System Provider

Interestingly, India is on the way to becoming the 5th global navigation system provider.

Currently, there are four global navigation systems: GPS from the United States, GLONASS from Russia, Galileo from the European Union, and BeiDou from China. India’s NavIC and Japan’s QZSS are regional systems that are designed to function more effectively within their respective regions.

However, these systems are expected to evolve into global navigation systems in the future.

Previous GSLV mission?

The last GSLV mission was the GSLV-F14/INSAT-3DS mission, which was launched on February 17, 2024. This mission helped position the INSAT-3DS satellite in a geostationary orbit.

The NVS-01, meanwhile was launched by ISRO, in May 2023. It was the precursor to NVS-02, using the GSLV rocket for the NavIC system. This mission was named GSLV-F12/NVS-01.

What's next?

The NISAR satellite: In February, the GSLV-F16 mission will launch NISAR, an advanced earth observation satellite developed in collaboration with NASA. Equipped with advanced radar imaging technology, NISAR will provide critical data on agriculture, natural disasters, and climate monitoring.