Navy experts were examining radio telemetry data Friday in an effort to learn why a Trident 2 submarine missile went off course and had to be destroyed 60 seconds after it lifted off on a test flight.

The failure was only the second for the Trident 2 in 13 test launchings from a land pad here. The weapon, able to carry 10 nuclear warheads, will be the most powerful in the Navy's arsenal when it becomes operational late next year.The $23.7 million three-stage missile vaulted skyward Thursday evening and darted quickly into a heavy cloud layer.

The Navy reported 20 minutes after liftoff that there had been a malfunction. A statement later said the Trident 2 had developed a problem during first-stage flight and that the range safety officer sent a radio signal that ignited explosive packages in the missile.

Debris from the shattered rocket fell harmlessly into the ocean several miles down the Atlantic tracking range to the southeast of here.

The Navy said the cause of the problem could not be determined immediately and that an investigation was underway.

The 44-foot Trident 2 was to have hurled a dummy warhead package to an ocean target several thousand miles to the southeast. The weapon has a range of nearly 6,000 miles, but the intended range Thursday night was not disclosed.

The test was the 13th of 20 land-pad launches planned here, to be followed by at least five submarine firings. The missile is scheduled to become operational late in 1989 and will be deployed initially aboard the new submarine USS Tennessee, the first of nine Trident subs planned by the Navy.

Each submarine will hold 24 Trident 2s, each of which will be able to deliver up to 10 nuclear warheads to different targets.

The Trident 2 test launch program began here in January 1987 and logged nine straight successes before suffering its first failure last January. Two more successes followed prior to Thursday night's failure.