National Missile Defense, Inflated Fabric Radome for Sea-Based X-Band Radar


The Sea-Based X-Band Radar (SBX) is a major component of the Ground-Based Mid-Course Missile Defense (GMD). The SBX is a mechanically steerable, phased-array radar antenna mounted on a self-propelled, ocean-going, semi-submersible platform. This advanced X-Band Radar (XBR) is housed within an inflated radome designed to protect the radar from the harsh sea environment and cyclones of the Pacific Ocean. SGH worked with Raytheon and ILC Dover to design the radome.

The air-inflated, fabric radome is 120 ft in diameter with a spherical top half and prolate bottom half. The radome fabric is made of vectran fibers and was built by ILC Dover. Working with subconsultants Oceanweather Inc. and CPP Inc., SGH’s completed following:

  • Established design wind conditions and performed wind tunnel tests
  • Characterized the fabric’s nonlinear material properties, including uniaxial and biaxial testing, and determined effects of handling damages and UV exposure on fabric strength
  • Conducted testing to determined creep rupture characteristics of the fabric under sustained loading due to internal pressure combined with wind loading
  • Performed nonlinear finite element analysis of the fabric radome, considering nonlinear material properties and large deflections along with the effects of wind-induced rippling resulting from low shear strength of the fabric
  • Incorporated the results of our analysis and testing into a reliability model, accounting for variabilities in wind loading and material resistance (e.g., degradation, handling damages, stress biaxiality, and sustained loading effects)

Project Summary



Completion Date
New Construction
Applied Science & Research | Advanced Analysis
Science & Defense
Raytheon Company
Specialized Capabilities
Science & Defense | Computational Mechanics | Physical Testing | Environmental Simulations

Key team members

Frank Kan
Frank Kan
Mehdi Zarghamee
Mehdi Zarghamee
Senior Principal