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How Zero-gravity Flights Work

Inside the G-FORCE-ONE

Doctors Peter Diamandis and Byron Lichtenberg founded ZERO-G in 1993 with the intention of creating a space entertainment and tourism company. NASA used to conduct zero-gravity flights using a Boeing KC-135A Stratotanker, originally designed as an in-flight aircraft refueling vehicle. Diamandis and Lichtenberg needed an aircraft that met FAA (Federal Aviation Administration) regulations (NASA is exempt from FAA certification, but commercial travel is not), yet could withstand the stresses involved in simulating weightlessness. The aircraft also needed to be less expensive to purchase and maintain than the KC-135A. They focused their attention on the Boeing 727-200.

Playing games in a zero-gravity environment
Photo courtesy of Zero Gravity Corporation
Passengers can eat candy in a weightless environment and
not gain weight ... at least until they land.

The 727 has many qualities that appealed to Diamandis and Lichtenberg. Most large airports in the United States can accommodate the aircraft. Also, because the 727 is still a major part of the fleets of many airlines, parts and servicing are readily available. And although ZERO-G made some minor modifications to the aircraft, the 727 met FAA regulations, including standards on noise abatement.

In 2004, the FAA granted ZERO-G the permission to conduct flights in a 727-200 using parabolic paths. The company flies over uninhabited areas that are out of the way of most commercial flight routes. Each flight takes place within an FAA-designated corridor about 100 miles long and 10 miles wide.

Photo courtesy of Zero Gravity Corporation
ZERO-G’s Boeing 727-200, G-FORCE-ONE

ZERO-G modified the 727-200 to better suit the company's needs. Crews removed most of the seating and created a padded, 90-foot-long corridor where flyers -- the company's term for passengers -- would experience weightlessness. The rear of the plane can hold up to 35 flyers and six crew members. Engineers designed a new hydraulic system that prevented air and hydraulic fluid from mixing in a weightless environment -- such a mixture could result in a loss of hydraulic pressure, making it very difficult to control the plane. The new hydraulic system is a closed system, meaning a series of valves prevents air and hydraulic fluid from mixing.

Engineers also designed a special accelerometer for the cockpit. The accelerometer measures the plane's speed and path through a parabolic arc. Because of ZERO-G's focus on providing entertainment to customers, the company felt that comfort of customers was an important concern (NASA relies on its pilots to follow the parabolic path on their own and is less concerned about the smoothness of the flight). Pilots can receive data on their flight path, making minor adjustments when necessary to make ensure each arc is smooth as possible.

Boeing designed the 727 to withstand forces from -0.1 G to 2.5 G. The g-load stresses during parabolic flight on G-FORCE-ONE range from 0 G to 1.8 G, well within the range of safety. ZERO-G regularly inspects the aircraft for signs of equipment fatigue and maintenance needs.

Thank You
Thanks to Dr. Peter Diamandis of the Zero Gravity Corporation for his input on this article.

The company's headquarters is in Las Vegas, Nev. Most flights originate from Las Vegas or the Kennedy Space Center in Florida, but because many airports can accommodate a 727, the company invites customers to charter flights based out of their nearest major airport, making it that much easier to achieve a lifelong dream of defying gravity.

To find out more about zero-gravity flights, check out the links on the next page.




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More Great Links


  • "A brief interlude in zero-G." New Scientist. Vol. 194, Issue 2602, 5/5/2007.
  • Dempsey, Robert, et al. "Thank You for Flying the Vomit Comet." The Physics Teacher. Vol. 45, February 2007.
  • Gold, Scott. "Floating Free and Queasy." Los Angeles Times. Sept. 15, 2004.
  • Personal interview with Dr. Peter Diamandis on July 20, 2007.
  • Spangenberg, Ray and Moser, Diane. "The World's Highest Rollercoaster." Final Frontier, Sept./Oct. 1988.
  • US Patent # 5,971,319. System for converting jet aircraft to parabolic flight operation.
  • ZERO-G Corporation