NASA STILL EAGER FOR X-33 TANK DAMAGE TO DELAY PROGRAM FOR 2 YEARS.

Byline: Jim Skeen Staff Writer

PALMDALE - Damage to a liquid hydrogen fuel tank in a test last fall will delay flight of the X-33 for at least two years, but NASA is still eager to see the rocket-plane through to completion, an official said Thursday.

NASA and Lockheed Martin officials are still trying to determine how much it will cost to continue the program in the wake of the Nov. 3 tank incident. An announcement on negotiations for continuing the program could come within a few weeks.

NASA and Lockheed Martin and its partners thus far have committed more than $1.2 billion to the program.

``I don't see any indication from NASA or from Lockheed Martin to withdraw from the program,'' said Gene Austin, NASA's X-33 program manager. ``This is a learning experience, and we're moving ahead. None of us want to see this program come to an end. We want to see the fruits of our labor.''

The wingless, wedge-shape X-33 is being developed to test several technologies considered for use in a reusable spaceship. That would allow the cost of getting payloads into space to drop from $10,000 to less than $1,000 a pound.

The X-33 itself is not designed to travel into space, but is expected to hit speeds of more than 9,000 mph.

The X-33 is being assembled in Palmdale, and flight tests will be conducted from Edwards Air Force Base. The first flights will go to a landing site in Utah; later flights will land in Montana.

The 29-foot-long, graphite epoxy tank was designed to carry 29,000 gallons of liquid hydrogen fuel and to serve as a major portion of the X-33's airframe. The X-33 was to have two such tanks, which would have taken up roughly half of the craft's airframe.

A joint NASA-Lockheed Martin investigation team found several causes for the tank failure, including manufacturing flaws, tiny cracks in the inner and outer skins of the tank, and the presence of a small piece of tape that interfered with the bonding process.

The damage to the tank was discovered in the wake of a Nov. 3 test at NASA's Marshall Space Flight Center in Alabama. During the test, the tank was subjected to loads it would experience prior to a launch.

After the test, the tank was drained and an engineer discovered fractures and rips in the tank's outer skin.

The small cracks in the inner skin allowed liquid hydrogen to seep into the tank's honeycomb core. Cracks in the outer skin allowed nitrogen gas used in the purge process to seep in.

The nitrogen and liquid hydrogen built up pressure inside the tank's honeycomb core. The gas inside the core expanded and the outer skin tore loose from the tank, said Robert Ryan, co-chairman of the investigation team.

Investigators also found a 3-inch-long, halnch-wide piece of tape that interfered with the bonding of the inner skin to the honeycomb core. It was not determined how the tape got there.

``The results of the investigation do not invalidate the use of composite materials for cryogenic tanks,'' the investigators said in a report released Thursday. ``The lessons learned from building and testing the tank and the incident investigation, if applied to composite cryogenic tank technology, should advance the technology and aid in the successful use of composites for cryogenic tanks.''

One of the decisions program officials will have to make is whether to go with aluminum tanks or continue to try to develop composite tanks. Lockheed Martin has completed a preliminary design review of aluminum replacement tanks.

In the meantime, assembly of the X-33 is continuing, including tests on the aircraft's electronic systems and flight control software.

``We're not just twiddling our thumbs,'' Austin said. ``We are making progress toward flight.''

CAPTION(S):

Shorter version ran in Business section, p. 2