•  India will take a big step towards achieving a credible nuclear weapon triad in February when its first indigenous nuclear submarine INS Arihant begins sea trials off Visakhapatnam. 

  • Top defence ministry sources say the "sea-acceptance trials'' (SATS) of INS Arihant are slated to begin "towards end-February'' after the completion of its ongoing harbour-acceptance trials (HATS). "It will take at least six months of extensive SATS and missile trials before the boat is ready for commissioning into Navy,

  • With INS Arihant's induction, India for the first time will brandish the most effective third leg of the nuclear triad - the ability to fire nukes from land, air and sea. The first two legs revolve around the Agni family of ballistic missiles and fighters like Sukhoi-30 MKIs and Mirage-2000 s jury-rigged to deliver nuclear warheads 

  • The  Big-5 has nuclear triads till now, with a total of over 140 nuclear-powered submarines. America leads the pack with 71, followed by Russia with about 40, while China, the UK and France have around 10-12 each. India did get delivery of INS Chakra, the rechristened Akula-II nuclear-powered submarine 'K-152 Nerpa'