Satellite Interception: US BMD Survives the Acid Test

Rarely would a defence R&D agency get an actual operational scenario to test the capability of a military system before attaining total technological maturity. The much-maligned U.S. Missile Defence Agency (MDA) silenced its long-time critics by utilising such an opportunity through a successful interception of a dysfunctional military reconnaissance satellite which threatened to hit the Earth with hazardous fuel. The seemingly successful interception and destruction of the orbiting satellite on February 21 by an Aegis Ballistic Missile Defence (BMD) system is a landmark in the US BMD development and in all likelihood would galvanise other such programmes currently under development-stage.

Being the first ever real-time outer space interception by a BMD system, the MDA used the ship-based Aegis system, the US’ only operational BMD currently deployed in Pacific Ocean (also employed by Japan and Australia). The Standard Missile-3 (SM-3), the main interceptor used in this mission, has a ‘hit-to-kill technology’ to intercept and destroy an incoming threat in ‘Exo-atmosphere’ (outside Earth’s atmosphere). With a 250+ km range, the SM-3 operates in conjunction with the Aegis AN/SPY-1 radars and sensors. For this particular mission, the Aegis was complemented by the powerful Cobra Dane and X-band radar (deployed on a floating platform) to impart precision tracking and targeting.

Mission-analysis reveals that the MDA has a multi-stage interception plan. The USS Lake Erie (Ticonderoga class cruiser) was to launch the first SM-3 and possibly a second one, if the first intercept failed. A second ship, the Decatur (Arleigh Burke class destroyer) kept ready a third SM-3 to be used if the initial two attempts failed. The SM-3s deployed in the USS Lake Erie was modified (through changes in its targeting software) to track the cold satellite, unlike its actual design capability of targeting heated warheads. The intercept convoy was deployed off the Hawaii Islands to track the satellite in its orbit and launch the interceptors when the intercept window was opened on the morning of February 21. Along with the radar and tracking systems, various space-based platforms were also put into service for data collection that fed to the mission controls at the Vandenberg Air Force Base and at the space command in Colorado Springs. In the end, the MDA mission proved successful after the first SM-3, reportedly launched from the USS Lake Erie, destroyed the satellite on impact thus taking out the target in the first hit, but sparking of debris some of which might re-enter the atmosphere in the coming days.

This landmark mission was necessary. The satellite planned to be destroyed had stopped communicating with mission control facilities shortly after it was launched 14 months ago, and thereafter began a slow descent towards Earth. The primary objective of the intercept mission was to destroy a fuel tank aboard the satellite which was holding over 450-kg of hydrazine, a toxic fuel. Had the tank survived a re-entry of the falling satellite, it could have caused serious danger to the point of impact and more so if it was a population centre. Though it is yet to be confirmed whether the intercept successfully destroyed the fuel tank, the mere fact that this was the first ever operational intercept outside Earth’s atmosphere by a US is significant in many ways, particularly as a major milestone in the global evolution of BMD technology.

The successful intercept assumes further significance for the US MDA which has increasingly been under the scanner for its slow progress. Such widespread criticisms led to unrelenting Congressional insinuations and budgetary cuts. While the Agency has sensibly deployed an operational system (Aegis BMD), it only partially clears misgivings on whether the Ground Based Mid-Course Defence System (GBMDS), the main US mid-course interceptor for exo-atmopsheric interception, is capable of undertaking similar interception in the future. Employing the Aegis BMD, which is an early ascent/late descent mid-course system, for this task carried a calculated technological risk as the system was assigned with a complex task of intercepting a target cruising at a high closing speed of more than 22,000 miles per hour. The Aegis BMD system has hitherto only been tested against slower-moving targets under pseudo-operational conditions.

Though the GBMDS and the Kinetic Energy Interceptor (KEI) are being developed to undertake interception at this speed outside Earth’s atmosphere, considering that these systems are yet to achieve development maturity, the MDA had no other options but to employ an operational system for this high-risk task. The other limited choices would have been to either use an Anti-Satellite (ASAT) system or employ extended-range theatre-wide defence systems like the Theatre High Altitude Area Defence (THAAD). Using the THAAD was an unfeasible option as the system is yet to be operationally deployed, and has the range (90-120 km) to undertake interception only at the threshold of the Earth’s atmosphere. This would have been highly risky as the interceptor might not necessarily gain the velocity to intercept the satellite outside the Earth’s atmosphere eventually causing the satellite or its debris to make re-entry into the atmosphere and causing damages to the area of impact.

On the other hand, deploying the ASAT systems, tailored for such tasks, was considered a political risk considering the momentum being generated against weaponisation of space and the usage of ASAT weapons. Washington had strongly criticized the recent ASAT test by China for destroying a defunct satellite, and had termed the action as a provocative step towards weaponisation of space. Taking the same method to destroy a non-military asset would have been viewed as hypocritical. Moreover, as soon as the Pentagon contemplated an outer space destruction of the satellite using a missile system, Russia and China lost no time in criticizing the US plans and unequivocally stating that it would not only harm other space assets but also lead to space weaponisation.

Though the SM-3 or GBMDS are designed as exclusive anti-ballistic missile systems with the objective of shooting down hostile ballistic missiles, their utility in attacking space assets of rival country cannot be underestimated. While the debate regarding the BMD had rarely touched upon the ASAT dimensions, the event of February 21 is likely to trigger a conundrum on the usage of BMD systems in outer space. However, the US officials have tried to reassure the international community on the distinctiveness of this mission compared to the Chinese ASAT test arguing that the Chinese effort was to test an ASAT weapon while their mission was not a missile test but to intercept the falling satellite in a much lower orbit than most working satellites.

Such arguments notwithstanding, the successful intercept of February 21 would clearly go down as a significant phase in the evolution of the BMD technology. Importantly, the MDA can now with rejuvenated confidence convince the Congress and its stakeholders on the reliability and efficacy of such systems in undertaking successful interceptions in actual operational conditions. This test could thus be deemed as a testament to the feasibility of BMDs.