WASHINGTON — Two former U.S. Air Force officers, including retired Brig. Gen. Simon “Pete” Worden, will lead a Pentagon investigation into the failure of the Falcon 1 rocket on its maiden voyage.

During his time in uniform, Worden was a leading advocate for the use of small satellites and small launchers like Falcon 1, developed by Space Exploration Technologies Corp. (SpaceX) of El Segundo, Calif.

Jan Walker, a spokeswoman for the Defense Advanced Research Projects Agency (DARPA), which paid for the launch, said Wo rden’s co-chairman in the investigation is Robert Paulson, a retired colonel who was honored in 2002 by the National Reconnaissance Office as a pioneer in intelligence space work.

SpaceX has indicated that a fuel leak and subsequent fire caused the Falcon 1’s main engine to shut down shortly after the vehicle lifted off from the Kwajalein Atoll in the central Pacific Ocean March 24 at approximately 5:30 p.m. EST. The rocket was carrying FalconS at-2, an experimental satellite built by students at the Air Force Academy.

“A fuel leak of currently unknown origin caused a fire around the top of the main engine,” Elon Musk, SpaceX’s founder and chief executive officer, said in a written update. “On high-resolution imagery, the fire is clearly visible within seconds after liftoff.”

Musk said the fire began about 25 seconds after liftoff and damaged the first-stage helium pneumatic system used to pressurize the rocket’s fuel tanks. Once that pressure dropped, the Falcon 1 rocket’s Merlin engine shut down about 29 seconds after liftoff, he added.

“I cannot predict exactly when the next flight will take place, as that depends on the findings of this investigation and ensuring that our next customer is comfortable that all reasonable steps have been taken to ensure reliability,” Musk said. “However, I would hope that the next launch occurs in less than six months. … SpaceX is in this for the long haul and, come hell or high water, we are going to make this work.”

Musk also said he was grateful for the support of his launch customers, who called in their messages after the incident.

“We will stand by them as they have stood by us,” he said.

The Falcon 1 , a two-stage rocket fueled by liquid oxygen and kerosene , is designed to launch payloads of up to 570 kilograms into low Earth orbit at a cost of $6.7 million . It features a reusable first stage, which is designed to parachute into the ocean for later pickup, servicing and reuse.

Prior to the failure , SpaceX officials were hoping to launch the second Falcon 1 rocket, carrying the Pentagon’s TacSat-1 satellite, later this year from Vandenberg Air Force Base in California . A Malaysian satellite and several smaller payloads also were set to launch from the Kwajalein site in February 2007, the firm said.

“Our plan at this point is to analyze data and debris to be certain that the … preliminary analysis is correct and then isolate and address all possible causes for the fuel leak,” Musk said. “In addition, we will do another ground-up systems review of the entire vehicle to flush out any other potential issues.”

Aside from the fatal fuel leak and fire, Falcon 1’s other systems appear to have performed as expected during its inaugural flight, SpaceX said.

Musk said the vehicle’s main engine, thrust vector controls, avionics, software and other systems functioned as planned. It does not appear that the rocket’s first-stage insulation, which wraps around the booster to insulate its supercold liquid fuel and was a source of some speculation early after the failed launch, played a role in the Falcon 1 rocket’s loss, Musk added.

The SpaceX chief said he and his firm are committed to rooting out the source of the failure, and that he believes in “maximum exposure” in terms of releasing information on the investigation as it is learned. Musk noted that SpaceX is not the first launch company to experience difficulties in the early going.

“Having experienced first-hand how hard it is to reach orbit, I have a lot of respect for those that persevered to produce the vehicles that are mainstays of space launch today,” Musk said.

Staff writer Colin Clark contributed to this story from Washington. Comments: tmalik@space.com, jsinger@space.com