Even more compelling than the failure of the Agni-III test is the need to keep the momentum of the programme going. India should avoid the kind of drift that overtook the Agni programme in 1990s when two of three tests were full or partial failures; yet after the 1994 test, the programme hibernated for the next five years. As it is, India's missile deployment programme limps behind Pakistan’s, which has had the convenience of acquiring its missiles off-the-shelf from China and North Korea and carrying out many more tests.
Indian defence officials are quick to give so many embellishments to success that it is difficult to separate fact from fiction. For one thing, many tests are needed before the missile can be declared fully developed for induction into an arsenal. The US and Russia typically carry out 20 or so tests before declaring a missile fully developed. The DRDO claims it has done so in the case of Agni-I and II, after three or four tests. Crucially, neither have been tested over land or on land targets. This is importantant because of the need to understand how the geomagnetics of landmass affect the guidance systems.
In contrast, the Ghauri — a derivative of the tested North Korean No-Dong — has been tested by Pakistan seven times already. Then there is the issue of accuracy. DRDO has claimed incredible accuracies for its missiles, but these are predicted accuracies, not tested ones as ought to be the case when a Circular Error Probable of a missile is worked out. Some claims don’t match up because Indian missiles use strap-down inertial guidance systems which are more prone to error than the mechanically gimbaled devices.
Agni III will be an important step forward for India’s missile programme because it is an entirely new vehicle designed for the purpose of carrying a nuclear deterrent rather than as a byproduct of other programmes. Agni-I and II were made by mixing and matching rocket stages from other programmes, notably India's first space launch vehicle SLV-3 and the Prithvi. As in the case of Agni-I and II, ISRO has probably played a key role in designing the two stages of the Agni III, both powered by solid propellent motors.
There has never been any doubt about the capability of Indian scientists in designing longer-range missiles. The issue is the speed with which DRDO is able to provide the other aspects— primarily guidance systems, re-entry vehicles that house the nuclear weapons, so on. The Agni is routinely displayed in Republic Day parades but on floats rather than all-terrain military vehicles, which would indicate they had been successfully inducted for use rather than mere display.