Wednesday’s A-SAT operation is the first major step towards building up a futuristic defence in India against attacks by space-borne systems and space docking activities. Such activity requires multi-agency coordination, including the Tracking and Command network of the Indian Space Research Organisation, the radar network of the Defence Research and Development Organisation and the excellent and 100 per cent reliable communications link between the various ground stations, radars and computational infrastructure.
This mission was accomplished with the help of good computational capability, a precise triangulation algorithm, automated launch and control of missile, accurate, orbital and position estimation of the satellite and various other systems. The scientists and all other personnel of both Isro and DRDO deserve the entire nation’s hearty congratulations!
While reports talk about China’s earlier space test in 2007, the destruction of the satellite was a slightly easier task as it was at a higher orbit and therefore the velocity of the satellite was slightly less than that of the missile.
The physical cross-section of the LEO (Low Earth Orbit) satellite could be between, say two square meters to a maximum of six square meters. The radar’s section will depend on the aspect angle with respect to radar. Hence, to precisely determine the position of the satellite, a multi-pronged approach is used where a network of radars, the satellite ground tracking network, if possible optical tracking, etc, are used, and then the position or more precisely the arc of the orbit of the satellite over Indian territory or may be over international waters is determined and selected with high levels of accuracy.
After the launch of A-SAT, and say within a 100-200 meter vicinity of the satellite, the missile seeker will guide the missile (Seekers could be infra red (IR), radio frequency (RF) active or passive, laser/optical seekers). India’s A-SAT employed an IR seeker. The whole process is like seeking a coin and targeting it in a heap of hay under dynamic conditions, in a very limited period of time. The role of the seeker is very critical as it helps to home in on the target and hits it without delay of even a nano second.
Therefore, it is a major achievement and needs a lot of appreciation by the entire country.
When a satellite is orbiting in LEO (300 km from earth), it will travel at speeds of 7-8 km per second, but the speed of the missile will be 3 km per second, so even a millisecond difference will mean that the missile will miss the target by several meters. Therefore, the accuracy of the timing, and finding the orbital position of the satellite will be very critical in order to hit the bull’s eye over Indian territory during such a mission.
In future, India would be well advised to emulate the United States and Russia, which have positioned satellites in space to control and track the launch of missiles and also photograph and trace the target with much higher accuracy. This would help in hitting the targets even over international waters rather than over our own territory.
There are subdued reactions to the Wednesday’s A-SAT test by various countries given the present geopolitical situation. However, in future, if an international treaty on such activities is signed, India will be treated at par with the United States, Russia and China. This activity was conducted only to demonstrate the capability and preparedness of the country for any kind of warfare in space. It is not a routine activity, and no administration would like to load its infrastructure for such tests.
Anti-satellite weapon systems have a long history and were a product of the Cold War hostilities between the United States and the then Soviet Union during President Ronald Reagan’s administration in the 1980s, which led to the so-called “Star Wars” programme. These weapons came back into popular currency after China conducted an anti-satellite missile test on January 11, 2007. The target was a Chinese weather satellite — the FY-1C — which sailed at an altitude of 865 km. A year later, the United States launched “Operation Burnt Frost”, the code name to intercept and destroy a non-functioning US National Reconnaissance Office (NRO) satellite named USA-193. Back home, while “Mission Shakti” may have targeted an object in outer space, India has long developed the capability to intercept incoming missiles.
In 2011, a modified Prithvi missile mimicked the trajectory of a ballistic missile with a range of 600 km. Radars at different locations swung into action, tracking the “enemy missile”, constructing its trajectory and passing on the information in real time to the Mission Control Centre (MCC) to launch the interceptor, an Advanced Air Defence (ADD) missile. It had a directional warhead aimed at the adversarial missile before exploding to inflict damage on it....