India’s Defence Research and Development Organisation (DRDO) announced on 2 November 2022 the successful interception flight test of the Air Defence-1 (AD-1) interceptor of what is described as Phase II of the country’s Ballistic Missile Defence (BMD) programme. 

Having described the test as a ‘maiden’ successful flight test, the interception off the coast of Odisha in principle takes India to the select club of countries with the capability to undertake exo-atmospheric (outside Earth’s atmosphere) interception. This implies the capability to intercept and destroy incoming or enemy missiles in outer space when longer-range missiles will be in the mid-course of their flight and will be on a ballistic cruise on a predictable trajectory. 

However, it is important to note that the DRDO has not mentioned whether an actual exo-atmospheric or outer-space interception has taken place. The press release states that “the AD-1 is a long-range interceptor missile designed for both low exo-atmospheric and endo-atmospheric interception of long-range ballistic missiles as well as aircraft.” 

Having mentioned that the interception was undertaken “off the coast of Odisha” could be an indication that actual interception might have been either upper endo-atmosphere or in the low-earth area. 

Almost all other nations with an ongoing missile defence programme have exo-atmospheric interceptors, which, when deployed and operated alongside endo-atmospheric (within Earth’s atmosphere) could provide for nationwide coverage or a comprehensive multi-layered architecture that could enable interception of enemy missiles in all phases of its flight. 

The phases are: boost (minutes after launch and still within Earth’s atmosphere), mid-course (entry into outer space for longer-range missiles or cruise/ballistic course of flight for shorter-range systems) and terminal (when the longer-range payload makes re-entry into Earth’s atmosphere or surges towards its target). 

While the Ground-based Mid-course Defence (GMD) system is the exo-atmospheric mainstay for the American missile defence programme, it also has the Standard Missile 3/6 (SM-3/6) which has low exo-atmospheric and upper endo-atmospheric ranges as claimed for AD-1. The Russians are developing the S-500 for exo-atmospheric capability though the Galosh interceptor of the Soviet-era architecture and the Gorgon of the late 1980s are supposed to have exo-atmospheric interception capabilities. 

The Chinese exo-atmospheric platform was known to have been tested in its third missile defence flight test in February 2018 which was then claimed by the Chinese official news agency as a ground-based mid-course interceptor, which was christened as Dong Neng-3 (DN-3/KO009). Israel recently started working on upgrading its upper-end endo-atmospheric mainstay, the Arrow 2, to an exo-atmospheric platform, the Arrow 4, in partnership with the American missile defence programme. 

Breakthrough for the AD programme 

The highlight of the 02nd November test was the declaration by the DRDO that this was a ‘maiden’, ‘successful’ flight test of the AD interceptor, and that it is part of Phase II of the BMD programme. The declaration holds relevance as it formally announces the 2nd phase of the missile defence programme and also the first successful test of the primary interceptor of the second phase. Some elements of the programme also seem to have been renamed. 

The AD programme was launched close to a decade ago as the second phase of the missile defence programme, without specifying so, and signified the quest for an exo-atmospheric interception capability. The pivotal objective was to develop an exo-atmospheric capability or systems/platforms that could target incoming missiles with over 3500–5000 km range, at an interception altitude of 120–150 km. 

India’s security planners expected such a capability to endow nationwide coverage against longer-range and faster Chinese and Pakistani missiles as well as the ability to intercept nuclear-tipped missiles as farther out in outer space. 

There were significant imperatives that prompted such an objective. Foremost is the realization that the existing missile defence platforms, namely the Advanced Air Defence (AAD) and Prithvi Air Defence (PAD) were essentially endo-atmospheric systems that are capable of providing only point, area and zonal defence. 

While the PAD has interception coverage against missiles with a 1000–2000 km range at altitudes of 50–80 km, the AAD system covers shorter-range missiles, with interception altitudes of 15–30 km. Despite both being essentially endo-atmospheric interceptors (below the 100 km altitude), the DRDO had initially projected the PAD as an exo-atmospheric interceptor, with its own definition of range. 

Even with a deployment architecture that facilitates overlapping coverage, the PAD-AAD combine could only provide a modest-to-accurate point as well as area defence against short and medium-range missiles emanating from Pakistan and China. Going by its proclaimed range, the PAD is supposed to be capable of targeting Pakistani systems like the Ghauri-I and Shaheen-II (under the 1500 km range) and, in principle, can provide extended area defence to parts of northern India, depending on the deployment pattern. 

A nationwide shield and strategic role

Suffice it to be pointed out that the raison d'être and original purpose behind any missile defence programmes will be to intercept, especially a nuclear-tipped missile, as farther out as possible in order to keep the territory and its population secured from damage or destruction. 

Hence, for any national missile defence programme, the foremost objective will be to develop the most ideal system that could intercept a missile outside the Earth’s atmosphere in the mid-course of its flight, though, of course, different nations have different threat scenarios which also included lower-tier and medium-range threats that operate in endo-atmosphere. 

Yet, a missile defence capability, particularly of a large nation, is deemed to be complete and credible only when it attains the ability for nationwide defence, which, incidentally the longer-range interceptors can provide. 

Hence, in order to counter the longer-range missiles (especially the Chinese) that could reach the Indian heartland and strategic assets located across the northern frontier (which Pakistan’s Shaheen III also intends to target), a longer-range interceptor that could do mid-course interception in wider and dispersed deployment is vital to achievingnation-wide coverage. 

This quest was launched through the AD programme, which initially had two systems PDV -1&2, probably a threshold system (upper endo-atmospheric and low exo-atmospheric) and a full-fledged mid-course interception system for deeper outer-space interception. 

The effort was initially reported to be handicapped by the absence of suitable long-range tracking radars (LRTRs), which was over the years addressed through an indigenous upgradation of the Greenpine radar.  

While the first phase of the BMD programme was seemingly based on the Prithvi platform including the targets, for the exo-atmospheric tests DRDO began trials with Agnisystems, supposedly for the interceptor as well as the targets. The reference in the press release to the “two-stage solid motor” confirms the imprint of the Agni platforms. 

Ambiguities about AD and PDV

The first test of the PDV-1 (and not the AD-1) to attain interception at a range of 120 km was conducted in April 2014. Though the DRDO initially claimed the mission was successful (in terms of inertial guidance and target seeking), the launch could not achieve a successful interception. 

A senior DRDO official later confirmed to this author that the interception could not be achieved and that more tests have to be conducted on the PDV before declaring it fit for deployment. 

Incidentally, the second PDV test in February 2017 was reported as a success. 

A PTI report quoting a DRDO official then stated that the “PDV mission is for engaging targets in the exo-atmospheric region at an altitude above 50 km of Earth’s atmosphere.” Also, the official while claiming that the PDV interceptor and two-stage target missile were “successfully engaged,” did not confirm whether actual interception had taken place. The report also confirmed that the mimicking target missile flew in from a distance of 2000 km.   

Thus, while there was no confirmation of successful interception, the reference to PDV operating at an altitude of above 50 km and the target approaching from 2000 km indicated operational parameters of the PAD system rather than an actual exo-atmospheric system. 

Amid such ambiguities and lack of clarity on the actual systems being developed and the outcome of test results, the DRDO had since the 2017 test been exercising visible caution by abstaining from a tight test schedule for the PDV, or hurriedly declaring success in the customary fashion as done for the PAD and AAD projects. 

The latest test, hence, attains significance as it embodies a breakthrough in phase II of the programme after a gap of over five years. However, terming the interceptor AD-1 only adds to the ambiguity on the fate of PDVs and whether the PDVs have been rechristened as AD. Whatever the nature of restructuring and renaming, the one thing that is clear from the test is the actual pursuit of an actual exo-atmospheric capability. 

A revival of the missile defence mission?

The flight test and its public announcement confirms that the missile defence is alive and kicking. For, the fate of the programme was shrouded in doubt and secrecy with the government remaining tight-lipped on the current status of both AAD and PAD and their deployment. 

After an unusually high rate of successful interception in the initial testing series till around 2012-13, the DRDO had declared the system as operational and ready for deployment to protect the national capital region (NCR). A satellite recce by this author of potential air defence deployment of the Indian Air Force in the NCR did not give concrete indications about any such deployment. 

Further, the government has also remained mum about their status even as a big-ticket acquisition of the Russian S-400, with both air and missile defence roles, was undertaken during the last few years. Hence, the role and space for AAD and PAD in the existing or evolving architecture remains subject to speculation.  

Nonetheless, it is worthwhile to point out that the future of the Indian missile defence programme, in the current circumstances, is heavily weighed on the success of the AD and its potential variants, unless, of course, we get to hear more about the PAD and AAD. The future deployment of AD, in conjunction with other interceptor platforms and a wide array of surveillance and tracking systems remains at the heart of attaining nationwide coverage, be it in modest terms or for large-scale deployment (in order to cover both nuclear dyads). 

Similarly, there is a different set of challenges that cloud the lower end of the spectrum where the AAD system is supposed to provide point defence (along with existing surface-to-air missiles) but may still find the theatre challenging when subjected to below-the-radar air-breathing threats, like cruise missiles, in both air-launched and land-attack versions.