More than a decade ago, the National Aeronautics and Space Administration and a contractor passed up a chance to make the first stage of the Delta rocket immune to the type of short circuit that may have caused one to fail last week, the head of an investigation panel said today.
Lawrence Ross reported that a review of data from Delta flights revealed that a 1974 failure was caused by conductive contamination in an electronics assembly.
"This accident led, in 1974 and 1975, to an overall Delta program effort to protect electronics assemblies against internal electrical short circuits," he said. "At that time, the major stage contractors were requested to analyze their designs and to incorporate the changes necessary to provide the required short-circuit protection."
These changes were made in the second and third stages, but Ross said the first-stage contractor, the Rocketdyne Division of Rockwell International, recommended against the modification after reviewing susceptibility of the circuitry to conductive contamination.
"This recommendation was accepted by NASA," Ross said.
He said that, as a result of last Saturday's Delta failure, which he said appears to be associated with an electrical short in the first stage, "the review board is reassessing the technical basis for the decision not to provide the Rocketdyne relay assembly with protection against conductive contamination and will establish if, in fact, a connection between this decision and the accident may exist."
The failure broke a string of 43 consecutive successful Delta launches.
The failure occurred when the first-stage engine abruptly quit firing 71 seconds after liftoff. The rocket spun out of control and was destroyed by a radio signal from the ground that set off explosive charges in the vehicle.
Lost in the accident was a $57.5 million weather satellite.
Meanwhile, it was disclosed that another "workhorse" rocket -- the Nike Orion, which had flown successfully 120 consecutive times -- misfired over the New Mexico desert April 25.
The government, whose space program is under pressure because of the recent explosions of the much larger Titan and Delta rockets and the space shuttle Challenger, did not announce the failure of a Nike Orion rocket carrying a pollution-sampling device.
In response to questions from the Associated Press yesterday, the malfunction was described by Debbie Bingham, a spokeswoman for the Army Missile Range in White Sands, N.M., and Edward C. Zipf, the University of Pittsburgh geophysicist who conducted the experiment for NASA.
The Nike rocket dates from the early 1950s when it was developed as a ground-based antiaircraft missile. It was used in different military versions until the last one was retired last year from Nike Hercules batteries in Western Europe.
NASA has been using the surplus, solid-fuel Nike booster in combination with another solid-fuel, military surplus rocket, the Orion. In the configuration that failed last month, the rocket and payload combination was 30 feet long.
The rocket was to take Zipf's experiment to an altitude of 50 miles, but he said it got no higher than 6,000 to 7,000 feet. There, the burned-out Nike first stage failed to separate before the second stage Orion ignited.
The rocket veered off erratically and deployed the parachute that brought the $40,000 payload back to Earth with a few scratches but no data. All the rocket debris and the payload fell in the desert of the White Sands range.
Zipf's payload, weighing 800 pounds, had been used 14 times. It contains pumping systems that freeze samples of air that are collected into a pair of helium refrigerators at minus 450 degrees Fahrenheit.
At such temperature, the air turns to snow which is brought to the ground and measured for its constituent parts.
"We are going to fly again in August, this is just a momentary problem with one of these war surplus rockets," Zipf said. "There is no investigation of the rocket. It went largely unnoticed because it is such a small thing in the overall perspective of things and because the payload was not lost."
Meanwhile, serious safety concerns and ballooning cost overruns threaten the future of a key shuttle satellite rocket, which could further hamper America's ability to launch heavy payloads, an aerospace magazine reported today.
Citing internal NASA documents, Aviation Week & Space Technology magazine said the space agency has put on hold portions of the Centaur rocket program pending extensive reviews and a decision on "whether to proceed with or cancel the $1 billion effort."
The rocket, built by General Dynamics' Convair division, is crucial to NASA's plans to launch three interplanetary probes, one built by the European Space Agency, and at least six military spacecraft through the end of the decade.
Unlike previous shuttle satellite rockets, Centaur is the first such booster designed to be carried in the shuttle's payload bay that burns explosive liquid-hydrogen fuel.