Image taken from chase plane shows the rocket's out-of-control track. Photo: NASA-DFRC

NASA has announced the five-person accident investigation panel that will determine what caused the Orbital Sciences Pegasus booster with the agency's X-43A aircraft to malfunction during a botched launch Saturday.

The board will be led by Robert Hughes of NASA's Marshall Space Flight Center. He is the manager of the development projects office inside Marshall's Space Transportation Directorate.

Other panel members are:

• John Deily of Goddard Space Flight Center. He specializes in guidance, navigation and control.
• Joseph Lackovich Jr. of the Expendable Launch Vehicle launch services office at Kennedy Space Center.
• Victoria Regenie, deputy director of research engineering at Dryden Flight Research Center.
• Luat Nguyen of Langley Research Center's competency directorate.

NASA has not put a deadline on the board's inquiry, which will focus on volumes of data recorded from the rocket and X-43A during the launch. Video and still images were also taken during the flight over the Pacific Ocean by aircraft flying near the air-launched Pegasus, which could offer clues about why the rocket lost control.

"We don't want to pressure them," NASA spokesman Alan Brown said. "There is no timeline. We just want to find out what happened."

The space agency appointed the board members on Monday. They held a short meeting to get acquainted and organized on Tuesday, followed by a lengthy meeting on Wednesday at Dryden.

Orbital's L-1011 carrier aircraft at Cape Canaveral with Pegasus rocket and HESSI attached to its belly. Photo: NASA-KSC

As the investigation continues in California, a Pegasus rocket with NASA's HESSI solar flare research satellite remains grounded at Cape Canaveral Air Force Station in Florida.

NASA postponed the planned Thursday launch of HESSI to allow engineers time to unravel details of what likely caused the X-43A mishap and to ensure the same glitch won't strike again.

The X-43A was being launched by the first stage rocket motor of a Pegasus vehicle. However, the stage is modified with different thermal protection, a new guidance system and repackaged avionics.

The Pegasus that will carry HESSI also has two additional stages and a protective fairing to shroud the satellite during the ascent through the atmosphere.

Officials had targeted next Tuesday for the launch of HESSI. But NASA now says the launch isn't likely before the end of next week, at the earliest.

A meeting is scheduled for Friday to review the situation and possibly establish a new launch date.

If HESSI doesn't fly by June 23, the Pegasus vehicle will have to be returned to its home base at Vandenberg Air Force Base in California for servicing, including internal battery replacement.