Technical Information: Radiation Resistance

High-radiation environments historically have presented microwave system designers with a difficult coaxial cable choice: semi-rigid cable or externally shielded flexible cable. The problems associated with configuring and routing semi-rigid cables are well-known. Standard flexible cables with fluorocarbon jackets and dielectrics deteriorate when exposed to high levels of radiation. External shields add weight and complexity to flexible cable runs.

GORE^® Spaceflight Cables are engineered to withstand the severe levels of radiation found in many satellite applications. We combine radiation-resistant materials with our proven basic constructions to provide a practical, flexible cable for high-radiation environments. Our radiation-resistant cable retains the basic construction and performance of our standard microwave cable.

Our standard spaceflight assembly is suitable for most radiation environments. This assembly differs from our baseline ground cable in that it is manufactured with TEFZEL® radiation-resistant jacket material. This material ensures that the cable remains structurally sound during radiation exposure.

GORE^® Spaceflight Assemblies use dielectric cores identical to those found in our basic cable types. All Gore spaceflight cable types meet the generally accepted maximum vacuum outgassing rates for spacecraft (1.0 percent TML and 0.10 percent CVCM). The low or ultra-low attenuation of these cable types is retained, and the same insertion loss and VSWR guarantees apply.

Most connectors available for our basic cable types can also be selected for our radiation-resistant cable. When specified, the assembly termination can incorporate extreme temperature, non-outgassing materials and can be assembled to high-reliability spaceflight standards. All of our vented, multipaction-inhibiting SMA and TNC connectors are also available.

The type and intensity of high-energy radiation encountered in space depends on the trajectory of the spacecraft, the impingement angle of the radiation, and the presence or absence of external shielding.

Gore's standard spaceflight assemblies are characterized for mechanical and electrical performance at exposures up to 100 Mrad (see the effect of radiation on GMCA performance insertion loss change vs. frequency 28 cable graph below). After 100 megarads (107 rads) exposure, the jacket remains pliable, and the mechanical performance is only slightly affected.

For more information on radiation-resistant microwave coaxial assemblies, please contact W. L. Gore & Associates.