This Navy ManTech project addressed manufacturing issues associated with fabricating long lengths of vacuum-jacketed cryostat that meets Navy shipboard requirements. NASA, Kennedy Space Center photo
This Navy Metalworking Center (NMC) project addressed cryostat configuration and manufacturing issues associated with fabricating long lengths of flexible, vacuum-jacketed cryostats that meet Navy shipboard performance requirements.
For High Temperature Superconducting Degaussing (HTSDG) coil systems, the cryostat (a double-walled vessel used in conjunction with extremely effective thermal insulation with a high vacuum) provides the necessary insulation to maintain a very low resistance condition in the cable. The Navy intends to use HTSDG coil systems on future Navy platforms. The applications require long lengths of cryostats to provide the necessary insulation. Currently no U.S. supplier is capable of manufacturing flexible cryostats that meet application requirements. With the adoption of HTSDG coil systems for the Littoral Combat System (LCS) and other future Navy platforms, orders of cryostats for HTSDG will be over 7,000 meters annually.
This project included provisions to evaluate reliability performance, as well as proofing of fabrication techniques.
Using a domestic supplier for the HTSDG cable systems would result in an anticipated 30 percent cost savings, as well as diminished labor costs and installation duration due to a reduction in the number of cables to be pulled. The HTSDG cable systems would also reduce the overall degaussing system weight by an estimated 50 percent for most ship classes due to the reduced number of cables.
The project results will not be implemented at this time because industry participant Southwire was unable to commit the capital investment required to upgrade its manufacturing facility and support a domestic supplier. However, the project did realize the several technical accomplishments. A baseline cryostat insulation system was developed and validated via thermal performance testing. This insulation system, consisting of double aluminized Mylar® and polyester net for the reflector and spacer materials of the cryostat, was shown to perform better than the typically utilized double aluminized Mylar® and polyester (non-woven) fabric. In addition, current technology available from an existing vendor has been identified for forming, welding, and corrugating stainless steel sheet of the desired thickness ranges for the manufacture of HTSDG cryostats. Analyses have shown that this technology will be able to produce corrugated tubing that meets application requirements.
A follow-on project with another industry partner could easily leverage this work to its logical conclusion of a U.S. manufacturing capability for long-length cryostats.
StakeholderAnthony C. Smith
Naval Surface Warfare Center, Carderock Division
Oak Ridge National Laboratory
ASRC Aerospace/NASA Kennedy Space Center