One of our newest toys is called
JLENS (Joint Land Attack Cruise Missile Defense Elevated Netted Sensor) systems to Iraq to help defend offshore oil facilities from attack. This JLENS uses a 233 foot long, helium filled, unmanned blimp equipped with radar and other sensors. The JLENS blimp is about 2.5 times the size as the more familiar advertising blimp. Actually, the JLENS blimp is an aerostat, a blimp like vehicle designed to always turn into the wind and stay in the same place. The JLENS blimp is unpowered, and secured by a cable that can keep the aerostat in position at its maximum altitude of 15,000 feet. At that altitude, the JLENS aerostat can carry a two ton payload. The cable also supplies power, which means the blimp can stay up for about 30 days at a time before it has to be brought down for maintenance on its radars. Two radars are carried. One is a surveillance radar, the other is a precision track and illumination radar (PTIR). The surveillance radar provides long-range coverage (over 300 kilometers, exact range is secret), while the PTIR, which is a steerable system capable of tracking multiple targets, can focus in on items of interest.
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