India's first indigenous n-submarine INS Arihant to operate from 2015

"So, it will be a careful, step-by-step operation and as soon as we are comfortable with the step-by-step established parameters, the submarine would set course for the sea for designated and pre-determined further trials," the distinguished scientist observed.

He said he did not want to put a time-frame but would expect it to "happen in a couple of months - say March".

Chander did not disclose details about INS Arihant's weapons, but it is understood that its four tubes are designed to launch 750-km range K-15 missiles and 3,500-km range K-4 missiles. Both these are nuclear tipped, capable of destroying any large city.

INS Arihant will carry 12 K-15 and four K-4 missiles. There is provision to launch non-nuclear tipped Brahmos supersonic cruise missile as well as the 1,000-km Nirbhay which can be configured for both nuclear and non-nuclear warheads, and has some loitering capability.

All these missiles have been tested successfully from underwater pontoons.

India is reportedly looking at three or four nuclear-propelled Arihant-class submarines and a larger number - 10 or 12 - of nuclear propelled attack submarines of a larger class. The latter, designated internationally as SSN boats, move fast along with Carrier Battle Groups (CBGs) while the nuclear armed boats like the Arihant, designated as SSBN, stay in hiding for three or four months as part of deterrence strategy. SSN boats carry submarine launched cruise missiles (SLCMs) like the Brahmos, or Nirbhay.