Integrated Sensor Is Structure (ISIS) Airship

The ISIS program is developing technologies that enable extremely large lightweight phased-array radar antennas to be integrated into an airship platform. ISIS uses a large aperture instead of high power to meet radar performance requirements. This approach exploits the platform's size and conforms to the platform's limitations on weight and power. As the radar aperture grows larger, the tracking performance of the radar system increases exponentially.

Major technical challenges are the development of ultra-lightweight antennas, antenna calibration technologies, power systems, station keeping approaches, and airships that support extremely large antennas.

The goal of the ISIS program is to develop a stratospheric airship based autonomous unmanned sensor with years of persistence in surveillance and tracking of air and ground targets.

It will have the capability to track the most advanced cruise missiles at 600 km and dismounted enemy combatants at 300 km, and small vehicles under foliage up to 300 kilometers away – capabilities not possible from existing or planned air or space assets.

The airship will be use solar-regenerative power with fuel cells instead of batteries. They will be able to sustain airspeeds of 60 knots with bursts of 100 knots enabling them to relocate anywhere in the world within 10 days.

Capable of operating autonomously at 70,000 feet they will have an operational life in excess of 10 year and require no in-theatre ground support.

The airship will feature a dual (UHF/X-Band) aperture. In an operational system, these radars would be approximately 6,000 square meters in size (the size of 15-story building), and would be embedded into the structure of the airship.

Phase 1 of the ISIS program consisted of a feasibility study. During phase 2, contractors developed systems designs and critical technologies such as low areal density hull materials, lightweight low-power-density radar arrays, extremely low-power transmit-receive modules, and regenerative power systems.

In phase 3, which DARPA will conduct jointly with the Air Force, the program will develop a one-third-scale flight demonstration system using the technologies and manufacturing techniques demonstrated in the earlier phases of the program. The subscale system will consist of an X-band radar system that will be roughly 100 square meters in size

News

The Defense Advanced Research Projects Agency (DARPA) has selected Lockheed to develop the Integrated Sensor Is Structure (ISIS) phase 3 demonstration system in collaboration with Raytheon.