Tunnel 9 ready for the mission in 2014: Team successfully repairs critical infrastructure to continue busy test period

  • Published
  • By Dan Marren, AEDC Contributing Writer Director, AEDC White Oak Site
  • AEDC/PA
ARNOLD AIR FORCE BASE, TENN. --  Labor day, 2013 took on a whole new meaning when a significant amount of hard labor was required from people across many areas of AEDC to return the White Oak Hypervelocity Wind Tunnel 9 (Tunnel 9) to service for FY2014 after a faulty power cable failed.

The Tunnel 9 test facility is AEDC's highest speed test facility which operates on one of AEDC's remote operating locations in White Oak, Md. Tunnel 9 is unique in its aerodynamic and aerothermodynamics support for strategic reentry systems, missile defense and space access. As a remote operating location, infrastructure to support the facility operation, and assets that can be leveraged to repair and maintain it, requires special considerations as well as coordination from several organizations.

Tunnel 9 is currently in the midst of a very long test campaign, providing risk reduction and flight anomaly investigation for boost glide concepts in support of the Global Strike mission. Testing has been near or over capacity for quite a while and this trend is anticipated to continue into next year.

During the installation of a new power supply in the summer of 2013, the medium voltage (15 kV) power cable which provides electrical service was spliced. Soon after the splice was made we began to get low Resistance-To-Ground (RTG) readings on the power cable. Eventually the RTG problem was isolated to the cable run between the splice & the electrical substation. With so much high-priority testing yet to come, the decision was made to replace the entire 15kV power cable and have a highly reliable power source going into flight confidence testing.

Since facility downtime would greatly delay the current customer, the team came together, coordinated and cooperated across the base and with organizations locally in Maryland to minimize impact to the test customer. Talented individuals from contracts, engineering, maintenance and test groups formed a knowledgeable team that saw this important task through and supplied subject matter expertise every step of the way. Additionally, keeping the customer informed of our progress and schedule kept communications flowing so that there were no surprises.

It is estimated that the existing power cable was installed in 1965. This 15kV power cable was a single cable, approximately 2.5 inches in diameter, and was spliced several times. This cable run was estimated at 1,200 feet. For the replacement cable, and to maintain high reliability, the decision was made to request that the cable installation contractor pull three legs of the conductors.

The estimated replacement cost of the entire power cable circuit was around $100K. Our procurement was assigned to AEDC Contracting Officer Tony Clayborne. Due to the relatively small estimated cost and high priority of the procurement; we expedited contracting actions. A detailed statement of work package was developed quickly with the assistance of Maureen Burke in the AEDC Plans and Programs Division and Tony Acklen in the AEDC Test Support Division.

Soon after the contract was awarded, plans began on how the contractor would carry out the cable replacement work. There was a need for a significant electrical power outage in order to de-energize all of the cables in each manhole that the contractor needed to enter. The outage was complicated because several non-AEDC buildings are powered by the cables running through some manholes. The onsite cable replacement work started on Aug. 21, 2013. Pulling this much cable through several manholes without splicing required use of a specialized cable pulling truck that measured the pulling force on the cable, cut the old cable into four-foot lengths, and dropped the cut lengths into the truck bed.

Successful completion of the cable replacement resulted in a return to service for the test customer. The facility resumed testing and continues at a record testing pace moving forward.

This effort strengthened the relationships between this geographically separated location and the home base at AEDC in Tenn.