Rocket report cards: no two alike.

Rocket report cards: No two alike

With the United States and Europe struggling to restore their respective spacecraft liftoff capabilities, three investigating boards last week reported their preliminary findings on the three rocket failures that followed the Jan. 28 explosion of the space shuttle Challenger. The three different "expendable launch vehicles' represented three different organizations (NASA, the U.S. Air Force and Europe's Arianespace), and, apparently, three types of malfunction.

In the Air Force Titan 34D rocket that blew up on April 18 barely 800 feet in the air, doing an estimated $70 million worth of damage to launch pads below, the insulation lining one of the vehicle's two solid-propellant boosters apparently separated from its metal casing, letting hot exhaust gases burn through the casing and trigger the blast. Such a malfunction had never occurred before in a Titan, investigators said, and seemed to indicate no fundamental design flaw-- just a need for increased quality control and additional testing, expected to delay resumption of Titan launches until 1987.

Loss of the NASA Delta rocket that had to be destroyed from the ground when its engine shut off prematurely on May 3 has been blamed on a short circuit caused by wiring insulation damage due to in-flight vibration. Again citing no major defects, officials did acknowledge "some weaknesses' that could affect the wiring, and which could take several months to correct in other Deltas.

The most recent failure, the May 31 loss of a European Ariane rocket, was laid to problems with the igniter in its third-state engine. A previous Ariane had been lost last September, also due to problems with its third stage, but investigators of that mishap assumed that they had identified that difficulty from telemetered data and fixed it in subsequent copies of the rocket. The board looking into the latest disaster has submitted a list of 14 recommendations, including alteration and requalification of the third-stage igniter, though one Arianespace official acknowledges that the cause of the previous failure is now less certain.

One issue that has at least been suggested in the aftermath of so many launch disasters in such a short time span is the possibility of sabotage, though no direct evidence has been offered to support it. In an article by Tad Szulc in the July 6 Los Angeles Times, unnamed "French intelligence officials' are cited as saying that "now we have reason to ask that question,' but Arianespace chairman Frederic d'Allest said the following day that the Ariane investigation has offered "no reason to give credit to this kind of hypothesis.'