For Release: Aug. 30, 1995

Steve Roy
Office of Media Services
(205) 544-0034
steve.roy@msfc.nasa.gov

RELEASE: 95-56

MARSHALL LABORATORIES DEVELOP, TEST DC-XA TECHNOLOGIES

The Marshall Center will soon begin testing components designed to enhance the operational capabilities of the Delta Clipper-Experimental Advanced (DC-XA) vehicle, an unpiloted, single-stage rocket being developed by NASA and McDonnell Douglas Aerospace.

Marshall Center’s Structures and Dynamics Laboratory will run a test series, beginning in mid-September. The test will evaluate the strength characteristics of a new lightweight intertank composed of graphite composites. The DC-XA intertank, like the intertank of the Space Shuttle's External Tank, is a cylindrical structural connection joining the liquid oxygen and liquid hydrogen fuel tanks.

"Subjecting the intertank to a compressive load of 187,200 pounds will demonstrate the intertank’s capability to withstand 1.5 times its expected flight load and validate its composite, honeycomb sandwich design," explained test engineer Neil Tyson of the Structures and Dynamics Lab Structural Test Division. "Some 92 instrumentation channels will record data on the load, strain, structural change, temperature and humidity.

"Setting up a test like this is clearly the most demanding phase of the task. We’ll install dozens of gauges on the outer and inner surfaces of the test article to measure strain," said Tyson.

"After the instrumentation is installed, the test article will be mounted in the laboratory’s Gilmore universal test machine. The Gilmore will apply incrementally increasing series of loads to the intertank, while data is recorded at each step of the test."

In addition to Marshall technicians and engineers, technicians from Native American Services of Huntsville will support the test.

"Technology developed in the DC-XA advanced tests will be used in NASA’s Reusable Launch Vehicle (RLV) program," said DC-XA project manager Dan Dumbacher of Marshall Center. "Development of DC-XA enhanced technologies will provide the initial real-world experience for hardware design in such programs as the X-33 and X-34, leading to a low-cost reusable launch vehicle and will save NASA substantial resources, compared to previous development programs.

"The program represents a new way of doing business with the aerospace industry," said Dumbacher. "The program emphasizes and takes advantage of each participant’s technological, operational and innovative capabilities and eliminates duplication of effort. NASA and McDonnell Douglas are working together as partners.

"This particular test evaluates hardware that will save some 300 pounds on the DC-XA flight vehicle," Dumbacher said.

"We’re very pleased to be working on the Reusable Launch Vehicle (RLV) program," said Tyson. "We have excellent facilities capable of making an important contribution to the program and we anticipate testing more RLV components as the program progresses, including additional intertanks, fuel system components and flight structures."

Meanwhile, the first piece of DC-XA hardware designed by McDonnell Douglas and fabricated by Marshall Center’s Materials and Processes Laboratory, a graphite epoxy composite liquid hydrogen feedline for the DC-XA’s propulsion systems, was delivered in July to McDonnell Douglas and is currently completing its last step to flight acceptance, a vibration test.

"The feedline will carry liquid hydrogen from the fuel tank directly into a turbopump used in the liquid to gas conversion subsystem. This subsystem is used to supply propellants to the reaction control thrusters for vehicle attitude control," explained project team leader Philip Tygielski of the Propulsion Laboratory.

Conventional feedlines use heavier aluminum or stainless steel materials, while the composite materials used to fabricate the liquid hydrogen feedline for the DC-XA can reduce the article’s weight.

"The composite feedline underwent a rigorous series of tests at Marshall Center to prove not only the design, but the manufacturing process as well," said Tygielski. "The article was subjected to pressure tests, as well as thermal, hydrogen leakage and a variety of strength and damage tolerance tests. We’ve built and tested a first class product."

"The success we experienced in the development of the composite feedline was the result of a great team effort," said Tygielski. "A diverse team of engineers and technicians from the Propulsion and Materials and Processes Laboratories and McDonnell Douglas designed, fabricated, and tested the article in less than a year. In fact we completed the task almost a month ahead of schedule. Planning and decision making was decentralized, giving the team authority to quickly overcome many challenges, using the expertise of each team member. This project is a great example of industry and NASA working together to produce a great product," according to Tygielski.

Other planned DC-XA project enhancements to be tested at Marshall Center include a liquid hydrogen tank and a liquid-to-gas converter assembly in the flight reaction control system.

The first test flight of enhanced technology of the DC-XA components is scheduled for April 1996. Marshall Center is the host center for the Reusable Launch Vehicle (RLV) program.