RAS question
Which of the following is NOT among the three operational NavIC satellites as of March 2026?
Correct answer: (D) IRNSS-1F.
IRNSS-1F was not among the three NavIC satellites operational for positioning, navigation and timing services as of March 2026 after its on-board atomic clock stopped functioning on 13 March 2026.
Explanation
IRNSS-1F had stopped providing positioning data by March 2026. GPS World, drawing on ISRO’s announcement, states that IRNSS-1F completed its 10-year design mission life on 10 March 2026 and that its procured on-board atomic clock stopped functioning on 13 March 2026. After that failure, the satellite continued in orbit only for one-way broadcast messaging services, not for positioning, navigation and timing. IRNSS-1B, IRNSS-1L and NVS-01 remained the three NavIC satellites operational for PNT services across the Indian subcontinent. Therefore, IRNSS-1F was not part of the operational NavIC PNT set.
Why the other options are wrong
- (A) IRNSS-1B remained one of the three NavIC satellites operational for PNT services.
- (B) NVS-01 remained part of the operational NavIC PNT group.
- (C) IRNSS-1L remained one of the three satellites providing NavIC positioning, navigation and timing services.
Concept
India’s regional navigation system and the operational status of space assets are recurring RAS Science and Technology themes. Factual updates on ISRO programmes often decide close MCQs.