Steam and smoke billows around the second Delta 3 moments before liftoff in May 1998 at Cape Canaveral's pad 17B. Photo: Boeing

After suffering a pair of stinging failures in its first two launches, Boeing's third Delta 3 rocket will fly without a paying cargo this week as the company tries to build confidence in the new vehicle.

Officials announced in June the next Delta 3 would loft a dummy satellite into Earth orbit because a suitable payload could not be found in time.

"We felt it would be better to fly the vehicle now rather than wait for a potential customer as time went on," Jay Witzling, Boeing's director of the Delta 3 program, said in an interview when the decision was made.

"We have spent the last couple of months to get the vehicle ready to resume flight readiness. In parallel we have been working with a number of our customers to see if we could get an early launch with Delta 3. Unfortunately, we could not match up any of the schedule requirements that our satellite friends were having with our desire to essentially mitigate the risk on the rocket and fly it as early as we feel we were ready to go."

Boeing will spend around $85 million for the flight in an effort to posture itself to attract future launch contacts with a proven Delta 3 and the next generation Delta 4 rocket family, which will use some of the same parts when the new boosters debut in 2001.

"With the market essentially being a little bit on the soft side at the moment we felt it was more imperative to have the rocket ready and flown and be in position when the market turns up," Witzling said.

"If we waited so we could meet customer schedule requirements, we would pass up other opportunities for Delta 3 and Delta 4 launch services," said Gale Schluter, vice president and general manager of Boeing Expendable Launch Systems.

The launch is scheduled for Wednesday from pad 17B at Cape Canaveral Air Force Station, Fla. A four-hour launch window will be available from 7 to 11 a.m. EDT.

Boeing had faced waiting until at least October before launching the next Delta 3 rocket. That is when ICO is supposed to send a satellite into space for the global mobile communications system. ICO has purchased a total of five Delta 3 rockets, but its ongoing restructuring after bankruptcy has raised doubts about when the international consortium will use its first launch.

Two early setbacks
The first two Delta 3 launches in 1998 and 1999 ended in failures.

The maiden flight on August 26, 1998 was doomed by a guidance software error that ultimately caused the rocket's steering system to run out of hydraulic fluid. The two-stage rocket lost control and exploded 72 seconds into flight, destroying PanAmSat's Galaxy 10 communications satellite aboard.

An RL-10B2 upper stage engine like the one used on Delta 3. Photo: Pratt & Whitney

The most recent launch on May 4, 1999 made it to space, however, the RL-10B2 liquid-fueled second engine, built by Pratt & Whitney of West Palm Beach, Fla., ruptured due to faulty manufacturing of the powerplant's combustion chamber. Loral's Orion 3 communications satellite carried by the rocket was released into space, but in a worthless orbit.

Over the past year officials have conducted an exhaustive investigation that revealed the manufacturing and inspection processes were deficient at engine-maker Pratt & Whitney.

The hour-glass-shaped combustion chamber is comprised of four sections with strengthener strips brazed, or soldered, over the seams.

A 67-square-inch, diamond-shaped breach of its combustion chamber during the failed launch was caused by a rupture at a reinforcement strip.

The brazing technique used to attach the strips, started in 1997, was found to be faulty during the subsequent failure investigation because it could leave voids, or gaps, that make the joints weakened and susceptible to breaking during the rigors of launch.

The investigation found inspection records of the failed engine that indicated the quality of the brazing by Pratt & Whitney did not meet requirements.

However, Pratt & Whitney workers did not recognize there was a problem because of poor translation of brazing coverage requirements from design engineers to the screening criteria used by quality inspectors.

The first Delta 3 rocket sits atop pad 17B in 1998. Photo: Boeing

In the wake of the launch mishap, the manufacturing process has been changed and ultrasonic inspections are now performed in addition to the previous X-ray checks to ensure the engines are sound. Engines produced since the processes were changed are considered near-flawless, said Rick Arvesen, Boeing's chief Delta engineer.

"Clearly we found that were flaws in manufacturing process as well as the inspection process. The processes that are currently in place give us a valid indication of braze coverage, significantly better than we had before," Arvesen said today.

Earlier this year Boeing and Pratt successfully completed acceptance testing on the RL-10B2 engine that will be used in the return-to-flight launch.

Except for the crippling engine problem, the Delta 3 performed its full half-hour flight, including releasing the Orion 3 satellite.

"The flight we had demonstrated essentially all of the rest of the vehicle hardware and gave us a wealth of data to look at," Arvesen said. "We are confident we will have a success on the next mission and we have resolved the issues that occurred on the first two."

Mission demonstration
The upcoming launch will see the $85 million rocket embark on a flight very similar to the one performed last May. In fact, the dummy satellite was built to mimic the Orion 3 spacecraft carried on that flight.

"What we are trying to do with the mission basically is simulate our last mission with regard to how we flew so that we have directly comparable data. In doing that, we opted to simulate the basic characteristics of the Orion 3 payload with regard to mass, (center-of-gravity) and so forth," Arvesen explained.

The mockup satellite payload sits on a platform in the factory. Photo: Boeing

The 9,500-pound satellite mockup was built by Boeing at its facilities in Huntington Beach, Calif. The craft is made up of steel and aluminum plates and cylinders that produce the same dynamic characteristics of Orion 3, said Arvesen.

The upcoming launch will be known officially as DM-F3, or Delta Mission-Flight 3. It is scheduled to be the 280th flight of a Delta rocket dating back to 1960.

Engineers will outfit the rocket will special instrumentation, which is customary for any new rocket, to continue efforts to collect as much information as possible during launch.

There will be 120 extra measurements taken, such as pressures, temperatures and accelerations, from different locations on the rocket. Seventy measurements will be located on the second stage alone.

In addition, the rocket will carry an onboard video camera to watch the second stage engine during the flight.

"We are primarily focusing that on the engine and the engine systems to gather as much data as we can," Arvesen said.

Eye on the future
Besides proving the Delta 3 can become a viable rocket to launch larger satellites than the smaller but successful Delta 2 rocket, Boeing wants to show future customers the next generation Delta 4 will be safe to use.

The Delta 4 family of rockets, developed in conjunction with the U.S. Air Force's Evolved Expendable Launch Vehicle program, will use some of the same parts as the Delta 3, including the same second stage engine.

Boeing's future in the fiercely competitive commercial launch market is the Delta 4 line -- a family of five different rocket combinations capable of lifting varying sizes of satellite cargoes. Delta 4 will go head-to-head against Lockheed Martin's planned Atlas 5 fleet, Arianespace's Ariane 4 and 5 rockets and the Russian Proton vehicle.

To date, Boeing has 18 more Delta 3 rockets already purchased by customers through 2002 including 11 for Hughes Space and Communications International, Inc., five for Space Systems/Loral and two for Alcatel Space for SkyBridge. Over two dozen Delta 4 vehicles have also been sold.