New Delhi: The American sea-based missile defence system, Aegis, couldn't have got a better marketing push. The system used to shoot down a wayward spy satellite on Wednesday is at the heart of a renewed US invitation to India to join hands in putting together a missile defence shield. The US has proposed that the Aegis combat management system be installed on seven Indian frigates under a programme code-named Project 17 A. India's Larsen and Toubro and the Hyundai Heavy Industries have been roped in by American Lockheed Martin to present a joint bid for the Aegis to India. The shooting down of the satellite was however, the perfect marketing demonstration for the Aegis-based missile defence system. The flexibility of this system would allow for the integration of Indian missiles on a collective missile defence shield, should New Delhi so decide. Five other countries have pooled in 85 warships under the Aegis umbrella. Sea-based missile defences dramatically increase the chances of intercepting an enemy missile. The US is careful not to package it’s offer as a military alliance, an idea India is loathe to. The US offer extends to a multi-layered missile defence, which also includes the Patriot and the Thaad systems.