Qualified in Mains 2026? Persona: interview mentorship by our faculty, ₹499.Download result

VidBodh has grown into First Principles IAS. Same teachers, same free answer writing.

First Principles IASFirst Principles IAS

First Principles IAS · Current affairs

The monthly magazine, October 2026 · Science and Technology › Launch vehicles, satellites and applications

Printed on · firstprinciplesias.com/current-affairs

हिन्दी — Read in Hindi

NVS-03 reaches orbit on GSLV-F18 and gives NavIC its fourth satellite, the minimum for a position fix

LeadPrelims and Mains31 Oct 2026

Why in news

  • In October 2026 the Geosynchronous Satellite Launch Vehicle, on flight GSLV-F18, carried the NVS-03 navigation satellite from Sriharikota into its intended geosynchronous transfer orbit.
  • The launch takes NavIC back to its minimum operating configuration of four working satellites. Since July 2026 the system had only three, and three cannot give a position fix of their own.

Background

  • NavIC, Navigation with Indian Constellation, is ISRO's regional satellite navigation system. NavIC gives a position over India and about 1,500 km beyond its borders, and a timing service.
  • India felt the need after the Kargil conflict of 1999, when the country could not count on access to foreign navigation signals.
  • The design has seven satellites: three in geostationary orbit over the equator and four in inclined geosynchronous orbits, which trace a figure of eight over the Indian Ocean region each day.
  • ISRO named the first generation IRNSS, the Indian Regional Navigation Satellite System.
  • Every navigation satellite carries atomic clocks. A receiver finds its position by timing the signals from several satellites at once, which is why the clocks must agree to a few billionths of a second.
Open full size
How NavIC fell to three satellites and climbed back to four, 2013 to 2027 Green above the line: launches. Rose below: clock failures and losses. Dashed: due No launch for five years 2013 2015 2017 2019 2021 2023 2025 2027 2013 to 2016 Seven IRNSS satellites, the first generation, go up on PSLV. 2018 IRNSS-1I replaces the lost IRNSS-1H. 2023 NVS-01, the first second generation satellite: Indian clock, L1 band. October 2026 NVS-03 on GSLV-F18. Four working satellites again, the minimum for a fix. 2027 NVS-04 and NVS-05 due, in about five and ten months. 2016 to 2017 The imported rubidium clocks fail, all three on IRNSS-1A first. 2017 IRNSS-1H lost when the PSLV heat shield does not separate. January 2025 NVS-02 stranded in transfer orbit: its engine valve does not open. July 2026 IRNSS-1F ends its ten year life. Three satellites left: no position fix. A constellation is a programme, not a launch: seven satellites with ten year lives need a replacement about every year and a half. The five year gap, not one failure, took NavIC below four.
Open full size
Why a position fix needs four satellites Three distances give a point. The fourth corrects the receiver's clock 1 Signal Each satellite broadcasts its position and the exact time from its atomic clock. 2 Distance The receiver times the signal and multiplies by the speed of light: time becomes distance. 3 Three spheres Three distances fix one point in three dimensions, if the receiver's own clock were exact. 4 The fourth A cheap receiver clock is not exact. The fourth satellite supplies the measurement that corrects it. With three satellites Timing service continues No position fix of NavIC's own. Receivers fall back on GPS With four in view A position fix, the minimum operating configuration restored by NVS-03 in October 2026 Full service needs all seven slots filled, so NVS-04 and NVS-05 still matter
Open full size

How the constellation thinned

The first generation carried imported rubidium atomic clocks, and they began to fail in 2016.

Why three satellites give no fix

  • A cheap receiver clock is not exact, and the fourth satellite supplies the extra measurement that corrects the receiver's clock error.
  • With three satellites NavIC could only supply timing and augment the Global Positioning System.

What is new in NVS-03

First generation IRNSSNVS series
Atomic clockImported rubidium clocks, which failed earlyAt least one indigenous rubidium clock from ISRO's Space Applications Centre
BandsL5 and SL5, S and the L1 band that phone chips already receive
LauncherPSLVGSLV, with the indigenous cryogenic upper stage
Life and statusTen years. Most are now out of serviceNVS-01 and NVS-03 working, NVS-02 stranded
  • With L1, the band that GPS uses, NavIC can reach ordinary handsets and work alongside GPS.
  • To avoid the fault that stranded NVS-02, ISRO flew NVS-03 with its three pyro valves already open. A national committee cleared the step after ground tests.

Analysis

Clocks were the weak link.

  • The imported rubidium clocks failed early
  • The indigenous clock on the NVS series is the fix that matters most for the long run

Four is a floor, not a target.

  • With four satellites a receiver gets a fix only when all four are in view
  • Full service needs all seven slots filled
  • NVS-04 and NVS-05 matter as much as NVS-03

Navigation is critical infrastructure.

  • Banks, grids and telecom networks take their time from satellite clocks
  • The armed forces need a signal no other country can switch off

The way forward

Get phone makers to build NavIC L1 support into handsets sold in India, so that a civilian user base exists when full service returns.

Exam lens

  • Prelims:
    • NavIC: seven satellites, three geostationary and four inclined geosynchronous, covering India and about 1,500 km beyond
    • Four satellites in view are the minimum for a position fix. Three can only give timing
    • NVS series: indigenous rubidium atomic clock from the Space Applications Centre, and the L1 band
    • NVS-03 launched on GSLV-F18 from Sriharikota in October 2026
  • Mains: India's regional navigation system lost its ability to fix a position before its replacements flew. Explain how NavIC works, why the constellation thinned, and what the NVS series restores.

Asked before: Prelims 2023 · Prelims 2018 · Mains 2018 GS1

Show the questions
  1. Prelims 2023: Which one of the following countries has its own Satellite Navigation System?
  2. Prelims 2018: With reference to the Indian Regional Navigation Satellite System (IRNSS), consider the following statements : 1. IRNSS has three satellites in geostationary and four satellites in geosynchronous orbits. 2. IRNSS covers entire India and about 5500 sq. km beyond its borders. 3. India will have its own satellite navigation system with full global coverage by the middle of 2019. Which of the statements given above is/are correct ?
  3. Mains 2018 GS1: Why is Indian Regional Navigational Satellite System (IRNSS) needed? How does it help in navigation?

Connects to

Sources
  • The Hindu, 30 October 2026
  • The Hindu, 31 October 2026

Settled facts (dates of Acts, constitutional provisions, standing definitions) are from standard references.

Filed under: Launch vehicles, satellites and applications · The monthly magazine, October 2026