A Spray-On Cryogenic Insulating Material for NASA Which Prevents the Formation of Liquid Oxygen on Liquid Hydrogen Vent Lines

Abstract

The formation of liquid oxygen on the outside of liquid hydrogen vent lines poses a potential safety hazard on engine test stands at the NASA Stennis Space Center (SSC). Traditional foam insulations and other commercially available materials did not stand-up to the environment and were costly to install and re-install. To meet this need, an insulating material was developed by Composite Technology Development, Inc. (CTD). The material, CTD-620, is a 2-part epoxy system that cures at temperatures down to 10°C, in high humidity (85%), in less than 8 hours, and utilizes microspheres as the acting insulating component.

Extensive cryogenic testing was performed at CTD on adhesion, thermal contraction, thermal conductivity, and LOX flammability. Field trials were conducted at SSC. Results of these tests are reported. In addition to the insulating properties, excellent adhesive properties were observed.

Standard spray equipment was adapted by Venus-Gusmer, to make it easier to coat large areas. This equipment can apply over 3.2 kg (7 lbs) of material per minute. For smaller areas the material can be applied with a trowel.