The failure of the Navy's Trident 2 missile during a submerged submarine launch Tuesday isn't expected to stall production of its parts at two Utah companies.

Hercules spokesman Ted Olson said officials don't know why the missile test - the first launching from a submerged nuclear submarine - failed. The missile is built by Lockheed Missiles and Space Co. of Sunnyvale, Calif., while the first two rocket stages of the missile are produced in a joint venture by Morton Thiokol and Hercules."We don't know," Olson said. "I'm sure that the people in charge of the test don't know what happened. I know that there have been land-pad launches and that the program has gone extremely well."

Lt. Jim Wood, a Navy spokesman in Washington, said the exact cause of the missile explosion will be determined in a thorough investigation. Until the cause is pinpointed, questions about delayed missile production and design modifications - which would affect Hercules and Thiokol - can't be answered.

But Olson said missile testing occurs in the late phases of development, and Tuesday's test failure shouldn't stall production at the Utah plants. "We at Hercules and at Morton Thiokol have already started work on production. I wouldn't think there would be any serious delays or anything like that."

The Hercules spokesman said the Navy's missile program has been a long-term, profitable program for his company and Utah.

"This flight development phase is intended to work out these types of bugs," Wood said. "All we know is that it happened during the first stage of powered flight."

He said the Trident 1 missile suffered similar problems in the testing phase, and yet it was deployed on time. The Navy plans for the Trident 2 missile to be operational by this December.

An Air Force spokesman, reading a statement concerning the test-firing, said the first stage fired as planned and that a "malfunction during first-stage powered flight" caused it to "veer off course."

"It self-destructed after about four seconds of flight," he said.