Airborne Phased Array Radar (APAR): Mechanical Design Challenges & Trade Studies

The National Center for Atmospheric Research (NCAR), managed by the University Corporation for Atmospheric Research (UCAR), has commenced the development of a next generation, dual‐polarized Airborne Phased Array Radar known (APAR) that will aid in the research and development of better forecasting and prediction models for heavy precipitation / extreme weather events. This radar system will be installed on the National Science Foundation (NSF)/NCAR C‐130 scientific research aircraft. UCAR/NCAR has funded Ball Aerospace to develop the Active Electronically Scanned Array (AESA) for this system.

APAR’s mission is to fly in, under, over, and around weather systems and collect data on clouds and precipitation that will be used to generate more accurate weather predictions and forecasts. To fly such a mission, the exterior mounted radar system must survive the loads put onto it not only by the aircraft it is attached to, but also the weather and environment that it must go through. The ultimate design

• Produced a reinforced AESA structure to handle aircraft and aerodynamic loads, bird strikes, rain, lightning, etc. while staying within size and weight constraints.
• Addressed thermal and control challenges to keep the array an even temperature across the array face in the face of high AESA power dissipation and strict limits on available power, space and weight. The resultant AESA system has a unique liquid cooling solution to ensure reliable mission performance.
• Utilized subarray components that can easily be reached and replaced wherever the aircraft is stationed. AESA maintainability required strategic part placement of line replaceable units (LRUs) and drove the design for such.

This presentation will review some of these major design challenges, highlight the trades and decisions that were made, and give a preview of the structural and mechanical design of this new and exciting APAR technology.