Two down

When the second Delta III was launched on 4 May 1999 the new RL-10-B-2 engine on the second stage made its first burn successfully, but upon reigniting for the 162-second burn to enter geosynchronous transfer orbit it shut off after only 3.4 seconds, leaving the vehicle tumbling in an orbit with an apogee of 1,378 kilometres.78 The telemetry indicated that the engine had suffered two shocks, the first occurring 4.2 seconds after the first firing, and the more violent second one 3.5 seconds into the second burn, in this case accompanied by a rapid increase in temperature.79 An analysis determined that the engine had suffered "a 67-square-inch diamond-shaped breach of its combustion chamber''.80 The investigation focused on a fabrication process that had recently been introduced by Pratt & Whitney in which the soldered joints of the four segments of the hourglass-shaped chamber were reinforced by brazed seams of silver wire.81,82,8B Boeing blamed "poor manufacturing process control'' and "improper quality oversight''.84 Pratt & Whitney accepted the criticism. In fact, the breach was found to have developed at a seam that had leaked during a static firing, and the flawed brazing had left air pockets that allowed the joint to split. The fact that the repaired seam had survived a dozen later tests and its first inflight firing, only to fail upon restarting, prompted Pratt & Whitney to argue that the engine, with its large new deployable nozzle, must have been subjected to unexpected torsional stress, but Boeing said that there was no evidence of such stress.85,86 In future, the seams would be plated in place instead of being brazed, and then each unit would be put into an oven and baked.87 An independent mission assurance review led by Sheila E. Widnall, a former Secretary of the Air Force, concluded in November that the task of developing the Delta III had been underestimated by Boeing, which was ironic considering that it was to have been a low-risk upgrade of the Delta II. Nevertheless, the company ruled out schedule and financial pressure as factors in either of the two malfunctions.88,89

As regards the Orion 3 HS-601HP communications satellite that had been stranded, Loral accepted $247 million in insurance, and Hughes approached NASA on behalf of the underwriter with a proposal that the satellite be retrieved by a Shuttle in 2001 and fitted with a solid motor for the geosynchronous transfer orbit burn.90,9! However, the review of the rescue of Intelsat 603 in 1992 had concluded that the effort had not been cost-effective.9^93

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