The "Bharat Rakshak" website has extensive data and analysis that uses public domain data and ballistic calculations to show that the range is greatly influenced by use or non-use of thrusters on the RV (required for velocity trimming) for propulsion as a HAM (high-altitude motor). There seems to be room in the RV for about 200 kg fuel (solid or liquid) after allowing for a long but lightweight thermonuclear weapon. This RV integrated HAM is referred to as the half stage after the two solid fuelled stages. This stage provides a disproportional increase in range for a lighter RV payload. Thus development of lightweight nuclear weapons is paramount to the missile's range.