DuPont Aerospace of La Jolla was notified by NASA late last month that it could keep the two engines, which were part of a 19-year, $63 million research project to develop the innovative DP-2 aircraft. That action came after Congress refused to fund the problem-plagued program for next year.

NASA's decision drew criticism from Rep. Brad Miller, D-N.C., chairman of the House Science and Technology Committee's investigations and oversight subcommittee. On Thursday he asked NASA to turn over its records of the project.

“Please explain how turning over ownership of two jet engines worth an estimated $1.5 million to a for-profit commercial company is in the public interest,” Miller asked in a four-page letter to NASA Administrator Michael D. Griffin.

He noted that the Pentagon is preparing to auction all government property at the duPont Aerospace facility in San Diego.

Miller's inquiry is the latest turn in the much-criticized effort to develop the aircraft. Its demise became inevitable after Rep. Duncan Hunter, R-Alpine, failed to win congressional funding to continue the project next year. The DP-2's fate was sealed during a congressional hearing held by Miller's subcommittee in June, which spotlighted the Pentagon's lack of confidence in the program.

Defense officials over the years have voiced doubts about the aircraft. Hunter used his clout as the chairman of the House Armed Services Committee to keep the project alive through the insertion of special congressional funding each year. The aircraft was touted as a versatile weapons system that would combine the ability to take off from short runways and then hover like a helicopter through use of a jet exhaust stream called “vectored thrust.”

The Office of Naval Research, which oversaw the project, is reclaiming government-funded equipment and property used by duPont for the research. DuPont purchased the two engines in 2002 with the proceeds of a $3 million NASA research grant awarded to acquire them.

In an e-mail sent to duPont on Nov. 20, NASA contracting officer Heidi D. Shaw, who administered the grant, said it was the agency's “original intention that title to the two engines would vest with duPont Aerospace. This has not changed, and the engines are the property of duPont Aerospace.”

Miller said the NASA funding came from a $3 million congressional earmark inserted into an earlier veterans' spending bill by Rep. Dana Rohrbacher, R-Huntington Beach, another DP-2 backer.

Miller said NASA has the authority to ensure that the government “can retain ownership of government-furnished property and equipment.” He added that the subcommittee wants to ensure that a “private contractor does not improperly obtain ownership of government-furnished property.”

A NASA official who is following up on the congressional inquiry said yesterday that he was uncertain why the grant did not include a stipulation requiring return of the engines to NASA at the end of the project.

“Honestly, I don't know exactly why that decision was made (not to include the stipulation),” said Mark Manthey, chief of the exploration systems branch of procurement at NASA Glenn Research Center in Cleveland. “It is very unusual.”

Carol duPont, an executive with the company and the wife of president Tony duPont, defended keeping the engines.

“DuPont bought those engines with a grant that we worked on for NASA,” she said, adding that some of the funding was used to pay for research and flight testing. “I don't know who stirred this pot, where it came from, but that's grant money.”

A nonpartisan government watchdog group criticized the decision to allow the company to keep the engines.

“It's clearly an unusual arrangement and unfortunately so,” said Steve Ellis, a vice president at Taxpayers for Common Sense. “I think any fair-minded person would say, 'If we (the taxpayers) paid for something, it's ours. Why are we leaving it with a contractor?' ”