NASA intends to award a sole source contract to Zero Gravity Corp. (Zero-G ) for two parabolic flights aboard the Ft. Lauderdale, Fla.-based company’s commercially operated G-Force One airplane.

Zero-G introduced its service in September 2004 giving private citizens the opportunity to experience momentary weightlessness aboard a specially outfitted Boeing 727-200 cargo plane. G-Force One achieves this weightlessness for 30 to 35 seconds at a time by flying in parabolic arcs that temporarily counteract Earth’s gravity.

Although joy riders paying $3,750 for a two-hour flight aboard G-Force One make up the core of the company’s business, Zero-G since its inception also has marketed the aircraft as a microgravity research platform for any and all comers, including NASA.

NASA retired its KC-135 parabolic research aircraft last year but plans to field a DC-9 acquired from the U.S. Navy as a replacement this summer. NASA intends to use the aircraft for astronaut training and testing microgravity experiments.

Two prominent U.S. lawmakers, Sen. Sam Brownback (R-Kan.) and Rep. Dana Rohrabacher (R-Calif.), who at the time chaired separate congressional space subcommittee, wrote NASA late last year urging the space agency to buy rides from Zero-G as an alternative to owning and operating its own dedicated airplane. “We think that NASA should seriously consider the cost/benefits of chartering flights from companies like Zero-G rather than NASA operating its own planes for microgravity research,” the two lawmakers wrote in a letter to then NASA Administrator Sean O’Keefe. “Utilizing a private company like Zero-G, the costs could be shared and reduced between NASA and the public as more flights are booked for the same aircraft.”

Peter Diamandis, Zero Gravity’s chairman and chief executive officer, said in an interview in January that he did not see much chance of NASA scrapping plans to field the DC-9 but still was hoping to sell the agency at least some G-Force One flights. “We could offer them a backup capability,” he said in January. “We could offer them capabilities at [NASA] Glenn and Ames [research centers] and other cities where the DC-9 does not fly. We also offer them a larger airplane.”

NASA Headquarters published a notice May 19 on Federal Business Opportunities that it intends to buy two rides from Zero-G.

“Zero Gravity Corporation is a unique organization that has a [Federal Aviation Administration] certified aircraft to supply 2 reduced Gravity Flights for approximately 2.0-3.0 hours per flight,” the notice reads. “There is no other organization in the Parabolic Flight Services industry that can provide such a unique requirement of reduced Gravity Parabolic Flights.”

NASA spokeswoman Melissa Mathews said will pay Zero-G about $138,000 for the two flights.

Mathews said the mix of microgravity experiments NASA intends to fly aboard G-Force One “are still under review but will be related to environmental control and monitoring, human health and countermeasures, and others.”

Mathews also said NASA has not ruled out buying additional flights from Zero-G .

Brian Berger is editor in chief of and the SpaceNews magazine. He joined in 1998, spending his first decade with the publication covering NASA. His reporting on the 2003 Space Shuttle Columbia accident was...