India is developing a sub-sonic 1,000-km range cruise missile "Nirbhay" which can be used for a variety of applications. <br/><br/>This was disclosed by Dr V K Saraswat, Scientific Advisor to Defence Minister and Chief of Defence Research and Development Organisation in Bangalore today. <br/><br/>He also said the flight-trial of air-to-air missile 'Astra', having a range of 45 to 100 km, is on the cards.<br/><br/> Dr Saraswat said, India's armed forces are looking for long duration loitering missiles which can enter enemy territory, search targets such as radars, concentration of assets and a variety of movements of enemy, home-on the targets and bang them. <br/><br/>He made a strong push for deploying space-based sensors to keep tab on "adversaries" and gather intelligence via-a-vis defence surveillance. <br/><br/>Dr Saraswat said space-based sensors are a must for tracking and detection of movements of enemies. <br/><br/>Unless it has space-based sensors, India would not be able to make its ballistic missile defence system a "potent weapon", the scientist said.