Next, the plane is “pushed over” to create the zero-gravity segment of the parabola. For the next 20 to 30 seconds, everything in the plane is weightless. APRIL 2016 | 33 SPACED BY KATE EVERSON n 1976, a Boeing 727-200 began flying Braniff International Airways passengers to various locations in the Americas. Forty years later, the same aircraft flies passengers to the moon, Mars and beyond—or so they feel. Now known as Zero Gravity Corp.’s G-Force One, the plane uses a parabolic flight path to create microgravity inside its cabin, replicating lunar and Martian gravity, before releasing passengers into total weightlessness. How does it do this? From level cruise flight the pilot first pulls the aircraft steeply upward, so passengers feel about 1.8 G’s, or 1.8 times Earth’s gravitational pull. The pilot then performs a “pushover,” or transitions to a sharp descent. That transition and dive, which completes the shape of a parabola, makes everything not tied down in the aircraft momentarily weightless. But this 727 isn’t the only Boeing airliner to contribute to extraterrestrial studies. Repurposed aircraft have filled NASA’s needs, from a flying space telescope to space shuttle taxi. They also helped NASA prepare the first U.S. astronauts for space travel. “Our planes have always proved to be adaptable and quickly derived to fulfill other missions,” said Boeing historian Michael Lombardi. “That’s where we’ve really been able to support NASA—in those unique roles.” During the early years of America’s space program, overland transportation of oversized cargo for NASA was difficult or impossible, given the physical limitations of railroad tunnels, narrow roads, low bridges and power lines. Large rocket parts made on the West Coast, for example, had to be shipped to Cape Canaveral, Fla., by barge through the Panama Canal. Enter the “Pregnant Guppy,” a Boeing Stratocruiser heavily modified by Aero Spacelines Industries. In 1962, it featured the largest cargo compartment of any aircraft at the time, capable of carrying the 40-footlong, 18-foot diameter (12-meter-long, 5.5-meter-diameter) S-IV stage of the Saturn I rocket for the Apollo program. With the Pregnant Guppy, NASA was able to deliver crucial oversized cargo to the Cape in 18 hours versus 18 to 25 days aboard a barge, according to the space agency. The even bigger Super Guppy followed few years later. Today, NASA still uses one to carry outsized loads. The original Super Guppy flew more than 3 million miles (4.8 million kilometers) in support of Apollo, Gemini, Skylab and the International Space Station programs, according to NASA. The space agency also used a I A gentle pullout begins, which allows fliers to stabilize on the aircraft floor. This maneuver is repeated 15 times, with each taking about 10 miles (16 kilometers) of airspace to perform. During this pull-up, passengers will feel the pull of 1.8 G’s. The pilot then begins to pull up, gradually increasing the angle of the aircraft to about 45 degrees to the horizon, reaching an altitude of 32,000 feet (9,800 meters). Before starting a parabola, G-Force One flies level to the horizon at an altitude of 24,000 feet (7,300 meters). Photo: Apollo 11 astronaut Edwin Aldrin prepares for weightless conditions on board a Boeing KC-135 tanker prior to the first moon landing. NASA Note: Chart depicts the parabola flown by the Zero G 727.
Frontiers April 2016 Issue
To see the actual publication please follow the link above