HOUSTON — NASA expects to decide in 2007 whether to buy parabolic aircraft services from an established commercial provider or continue to use its own dedicated aircraft — perhaps operated by a private firm.

Titusville, Fla.-based Zero Gravity Corp. (Zero-G) has flown 100 flights since it began carrying paying passengers in September 2004 and now would like to sign up NASA as a major customer. Gunning for the NASA business, the company recently signed a $7.5 million lease/purchase agreement for a dedicated Boeing 727-200F cargo plane and plans to make $2.5 million in modifications to meet NASA requirements.

Under the previous agreement with Ft. Lauderdale, Fla.-based Amerijet International, Zero-G was limited to weekend use of two 727s that carried cargo during the week. Zero-G Chief Executive Peter Diamandis said the company will still have part-time access to a second 727 should it need it.

NASA has used parabolic flights for decades to expose payloads and passengers to brief periods of weightlessness for research and training purposes. The agency retired its storied KC-135 “Vomit Comet” in 2005, but replaced it the following year with a DC-9 it acquired from the U.S. Navy and spent $6.1 million getting it ready to enter service.

NASA officials said the agency is willing to buy parabolic flight services from Zero-G, but also wants to take a closer look at other arrangements, such as contracting out the operation of its own dedicated aircraft to an outside firm.

David Finney, chief of NASA Johnson Space Center’s Aircraft Operation Division here, said in a Dec. 5 e-mail that Johnson would continue to operate its modified DC-9 “unless a lower cost alternative is identified –with requisite assurances of flight safety, responsiveness and effectiveness — that can meet NASA’s [microgravity] research requirements.”

Finney said NASA headquarters officials in Washington had assigned the agency’s Cleveland-based Glenn Research Center responsibility for issuing a request for proposals next year to “identify a commercial company that could meet these requirements.”

NASA headquarters officials familiar with the coming procurement said that in order for Zero-G to win NASA’s business it will have to show that it offers the most cost-effective solution. The competition, these officials said, also is open to companies that want to propose operating the NASA-owned DC-9 under a contract.

Zero-G officials are steamed that NASA would even consider a so-called government-owned, contractor-operated deal given the fact that U.S. law and policy direct the agency to use commercial services where available.

Robert Walker, the former House Science Committee chairman and a Washington lobbyist who serves on Zero-G’s board of directors, told Space News that government-owned, contractor-operated arrangements of the type NASA is willing to consider “make a mockery of the whole concept of commercialization.”

Walker said Zero-G has cleared every hurdle NASA has put in front of the company, including getting certification from the Federal Aviation Administration and qualifying for the General Service Administration’s qualified bidders list.

“After clearing each one of the hurdles, a new hurdle appears,” Walker said. “Now left with no other options, at least some people inside NASA have decided to set up a competition.”

Walker said he takes small comfort in assurances from NASA that the competition will come down to the proposal that offers the best price for the services NASA needs.

“It’s a question of how you get to the price,” Walker said. “If you have an entity [in the competition] that doesn’t have to pay taxes on the assets, amortize the cost of the airplane or go get FAA certification, etc., well, then, they can pull any figure almost out of the air at this point.”

Walker faults Johnson officials concerned about job preservation for forcing an open competition in a situation where he feels NASA is not only justified in awarding a sole-source contract to Zero-G, but compelled to do so by a litany of policy guidance starting with the Commercial Space Act of 1998 and including the most recently issued U.S. space policy.

“Everybody I have talked to at [NASA] headquarters has been very positive and would love to see Zero-G offer a good price to taxpayers because they believe this would be a poster child for further commercialization efforts,” Walker said.

“The resistance is clearly at Johnson,” he added. “I gather that the further you go down in the bureaucracy the more entrenched the resistance is.”