An IDC Analysis with Inputs from Sayan Majumdar


New Delhi, 01 February 2004

In the futuristic scenario painted by Gen S Padmanabhan in his book reviewed by us last week he missed out on one very pertinent and potent future weapon for India in 2017 –– the use of submarines both conventional and nuclear powered, with the stated ‘second strike’ capability. It is quite likely that an Indian nuclear submarine will be in operation by then with sister submarines, as India’s second strike. The General discussed the ALH, Vajra a laser based weapon, advanced Akash AA systems and others in the book for the 2017 scenario but failed to include futuristic submarines and their communications. Several reports have suggested that the Indian Navy will have an operational nuclear powered submarine by about 2006. In such a scenario it is pertinent to shift focus to underwater VLF/ELF (Very Low Frequency/Extremely Low Frequency) and laser communications for effective coordination of the submarines with the National Command Authority.

The exact type of submarine the Navy may get remains to be seen but it could be a customized development of Russian Project 885 Yasen/Graney Class also referred to as Severodvinsk Class, which is a further derivative of the Project 971 Akula Class and features a significant cruise missile capability with eight vertical launch tubes aft of the sail. The hull is made of low magnetic steel, with spherical bow sonar and canted torpedo tubes. Another option could be a variant of Project 949A Antey Oscar II Class SSGN (Submarine, Nuclear powered, Cruise missile armed). Interestingly the dimensions of Oscar are greater than most variants of even ballistic missile armed submarines.

The Indian Navy had anticipated the importance of VLF (Very Low Frequency) underwater transmissions long ago. As part of an ambitious naval modernisation program, during the mid-1980s the Indian Navy had constructed a VLF (Very Low Frequency) broadcasting station in Tamil Nadu. Although not publicly declared, it was reported that the United States actively collaborated in the project, which was completed in September 1986.

The operational VLF facility can primarily be used by the Indian Navy to communicate with its SSKs (Submarine, Conventional powered hunter-killer). When nuclear submarines become operational, the VLF facility will permit Indian National Command Authority to issue launch orders to submerged subs at depths of several metres. VLF waves propagate almost a quarter of the globe away and are generally immune to atmospheric disturbances caused by nuclear detonations.

However on the negative side, their small bandwidth limits the rate of transmission of data, usually allowing only the operation of slow Teletype messages. Moreover the large terrestrial and static VLF facility would be vulnerable to enemy strikes and even if the VLF facility is shifted deep underground in “hardened” shelters, the communication antennae would be located above ground and will remain vulnerable. Thus an airborne VLF transmitter similar to the US Navy’s TACAMO (Take Charge And Move Out) should be seriously considered for procurement.

A powerful 200KW transmitter provides the VLF transmissions in TACAMO. The United States Navy utilizes an EC-130A/Q Hercules with a trailing wire antennae 10km long with a drogue parachute at the end. During transmission the aircraft flies in a continuous tight circle, which results in over 70 percent of the wire hanging straight down and acting as a relatively efficient vertical antennae.

Presently the E-6 Mercury is the airborne platform of the United States TACAMO Communications System. It provides survivable communication links between the United States NCA (National Command Authority) and Strategic Forces. Long range, air refuelable E-6 is a derivative of the commercial Boeing 707 aircraft equipped with four CFM-56-2A-2 high bypass ratio fan/jet engines with thrust reversers. The weapon system is EMP (Electro Magnetic Pulse) hardened. Mission range is over 6000 nautical miles. E-6B fulfils both TACAMO and ABNCP (Airborne National Command Post) missions.

The E-6 ABNCP modification program was established to upgrade TACAMO operational capabilities by incorporating a subset of USSTRATCOMM (United States Strategic Command) EC-135 ABNCP equipment into the E-6 aircraft. The modified aircraft have the designation changed from E-6A to E-6B. The E-6B modified an E-6A by adding battle staff positions and other specialised equipment. The E-6B is a dual-mission aircraft capable of fulfilling either the E-6A mission or the airborne strategic command post mission and is equipped with an ALCS (Airborne Launch Control System). The ALCS is capable of launching United States ICBMs (Inter Continental Ballistic Missiles). The E-6B is capable of performing both the TACAMO and ABNCP missions.

This modification enables USSTRATCOM to perform current and projected TACAMO and ABNCP operational tasking and the E-6B provides survivable C3 (Command, Control and Communications) force management communications for the NCA via multiple frequency band communications. TACAMO role is fulfilled in Russian Navy by a variant of Tupolev-142 Bear-J.

Attention has now shifted to laser based underwater communications. There is an optical window in the blue-green part of the laser spectrum, which enables transmission to penetrate the ocean at substantial distance. Power requirements are considerable and the system at least presently cannot be installed in artificial satellites. Thus as a tactical improvisation the laser is made to be ground based, preferably mobile, in perfect conjunction with a space based mirror with adaptive optics being used to produce a cohesive beam. Significantly, data transfer rate will be 300 times greater than ELF (Extremely Low Frequency) system although the “rerouted” laser may not penetrate the same depth.

The effective combination of nuclear submarines and underwater VLF/ELF (Very Low Frequency/Extremely Low Frequency) and laser communications will make our sea based nuclear deterrent optimally effective. The challenge lies in front of our national leadership and defence scientists to “secure” the proper system either indigenously or import it from established powers.

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