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

Anxious to prove its new Delta 3 rocket works, Boeing officials are debating options to fly the booster with or without a paying customer later this summer.

The company had hoped to launch the third Delta 3 rocket on May 31 from Florida's Cape Canaveral Air Force Station carrying a satellite for the ICO mobile communications network. However, London-based ICO has ordered that mission be delayed until October 5.

Boeing is now searching for a replacement payload to fly before the October mission and officials have not ruled out launching the $85 million rocket with just a dummy satellite in a demonstration flight.

A decision to launch a satellite mockup if a real customer can't be found will be made soon, the company says. Officials could also decide to simply wait until ICO is ready to launch in October.

The first two Delta 3 launches in August 1998 and May 1999 ended in failures.

The maiden flight 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.

The second try made it to space but the liquid-fueled second engine exploded due to faulty manufacturing of the powerplant's combustion chamber. The Asian telecommunications satellite carried by the rocket was released into space, but in a worthless orbit.

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 cargos. 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 and sold over two dozen Delta 4 vehicles.

The Delta family boasts a success rate over 94 percent in 277 launches since 1960.