Air Force Opens Inquiry Into Rocket Motor Explosion

Air Force officials Tuesday began mounting an investigation into the spectacular explosion of a new Titan IV rocket motor at Edwards Air Force Base, a dismal first test that could delay development of a more powerful booster engine.

Officials gave no immediate word on a cause of Monday’s blast, which heavily damaged the rocket’s test stand and sent a mushroom cloud containing hydrogen chloride gas high over the remote desert area about 100 miles northeast of downtown Los Angeles. No injuries were reported, and officials said the gas dissipated before reaching populated areas.

The test site at the Phillips Laboratory on the base remained closed to the media and the public Tuesday, and Air Force officials refused to provide details about the accident. But an Air Force statement said the test area was secure and posed no health or safety hazard to nearby communities.

The explosion, which created a giant fireball and scattered burning debris over a wide area, reportedly also damaged and burned nearby structures at the test site. But Phillips Laboratory spokesman Ranney Adams said he could not comment.

The blast was the latest in a series of delays to the Air Force’s efforts to develop a new and more powerful solid-fuel rocket motor enabling its Titan IV rockets to carry larger payloads, generally satellites. The Titan IV is the nation’s second largest capacity space vehicle behind the space shuttle.

Monday’s test was to be a stationary or so-called static firing of a single 112-foot-long, 776,000-pound rocket motor. But within a second of ignition, the rocket exploded into a huge fireball. In actual flight, a pair of the motors would serve as boosters for the main Titan IV rocket.

Bob Hessler, a spokesman for Delaware-based Hercules Aerospace Co., which has a $500-million contract to build 15 pairs of the new rockets, said the explosion will probably further delay the four other static tests that had been planned this year.

However, a spokesman said the Air Force can still meet its goal of using the new booster on Titan IV flights by 1993 if no major flaws are discovered.

Hessler said Monday’s first test had been slated for December until a crane collapsed in September at the same test site and dropped one segment of a similar rocket. A flash fire erupted, a technician was killed in the crane collapse and nine other workers were injured, none seriously.

Cal/OSHA officials originally sought fines totaling about $32,000 against Hercules and two other companies over that mishap. But blaming an error, Cal/OSHA officials said Tuesday that the actual figure is $25,170. A spokesman said Hercules has paid $8,000, and the other two companies have appealed.

Martin Marietta Corp., which has the main $7.3-billion contract to build 41 Titan IV rockets, said the new boosters were set to begin use in 1993. Four Titan IV rockets have been launched since 1989 using other boosters. At least one such launch is still set for later this year, a spokesman said.