ISRO ended 2024 on a high with the successful launch of its 99th mission - the Polar Satellite Launch Vehicle or PSLV-C60 - which has two significant experimental missions - SpaDex and POEM-4. Even as these experiments continue into the new year, the Indian space agency looks to ride the high wave and has made a big announcement.
Indian space agency chairman S Somanath declared that 2025's first mission will be ISRO's landmark 100th mission. It will be in January, he confirmed, but did not reveal the date it is being planned.
He however mentioned that the 100th mission will on-board the Geosynchronous Satellite Launch Vehicle or GSLV Mk-II rocket. The mission will be to add to the Indian satellite navigation system being set up and expanded over time by ISRO. The mission will be titled the GSLV-F15/NVS-02 Mission. The payload will be the IRNSS-1K satellite, part of India's navigation satellite constellation.
NVS or Navigation Satellite is part of the Navigation with Indian Constellation or NavIC - India's version of a Global Navigation Satellite Systems or GNSS - similar to the Global Positioning System or GPS often used worldwide.
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THE GSLV-F15/NVS-02 MISSION AND ITS OBJECTIVES
GSLV-F15 will be the 17th flight of India's Geosynchronous Satellite Launch Vehicle or GSLV. It will also be the 8th operational flight of the GSLV (11th overall flight) with India's indigenous Cryogenic stage.
The key objectives of the mission under the NavIC system will be to aid:
- Precision military activity
- Strategic applications
- Terrestrial, aerial, and maritime navigation
- Precision agriculture
- Geodetic surveying
- Emergency services
- Fleet management
- Location-based services in mobile devices
- Orbit determination for satellites
- Marine fisheries
- Timing services for financial institutions, power grids, and other government agencies
- Internet-of-Things (IoT) based applications
ALL ABOUT THE NVS-02 / IRNSS-1K SATELLITE
NVS-02, as the name suggests, will be the second in the series of 2nd-generation navigation satellites and the ninth satellite in the Navigation with Indian Constellation (NavIC). Just like its predecessor - NVS-01 - the NVS-02 will most likely have two kinds of payloads - navigation payload and ranging payload.
Image Credit: ISRO
The navigational payload is what transmits signals to users on Earth. It does so using three bands in the spectrum - L1, L5, and S band. Since time is relative, and many factors affect it, to have the precise time, an atomic clock is on-board this payload. It is usually a Rubidium atomic clock. A rubidium atomic clock measures the length of one second by counting the oscillations of rubidium-87 atoms. These clocks are so powerful that they have an accuracy of about three parts in 10 quadrillion, which means they can keep time within one second over 100 million years.
The ranging payload consists of a transponder. This helps the navigation satellite transmit time-stamped navigation signals to the receivers at the ground station. This information is then processed at the end-user stage to derive their exact position, speed, and time. This helps in providing seamless and non-stop service irrespective of weather conditions on Earth.
The 2nd-generation satellites in NavIC have a much more robust encryption system to keep all communications completely secure.
As in the case of US' GPS, India's NavIC also has dual use - civilian and military. NavIC was earlier named IRNSS or Indian Regional Navigation Satellite System, which had a much more limited coverage area.
Currently there are four global navigation systems - GPS from USA, GLONASS from Russia, Galileo from European Union, and BeiDou from China. India's NavIC and Japan's QZSS are still only regional, but may be global in the future.
The last GSLV mission was the GSLV-F14/INSAT-3DS Mission, which was launched on February 17, 2024. It placed the INSAT-3DS satellite payload into a GTO or Geosynchronous Transfer Orbit. The last GSLV mission used for NavIC was in May 2023, when ISRO launched NVS-02's predecessor NVS-01. The mission was titled GSLV-F12/NVS-01 Mission.
