KC-135
The KC-135 reduced-gravity aircraft in flight.The KC-135 is a modified Boeing 707 four-engine turbojet that NASA uses to simulate conditions of weightlessness. In a typical flight, it traverses the Gulf of Mexico in a series of large parabolic arcs. Peaking at 32,000 feet, the plane then dives to 24,000 feet, its fuselage pitched down at 40 degrees. At the top of each parabola, passengers lose all sense of gravity and become weightless for a period of roughly 25 seconds. When the airplane comes out of the dive and begins its next ascent, the plane pitches upward at about 50 degrees and passengers on the craft are subjected to forces up to 1.8 times that of gravity. This climbing and diving is repeated thirty times in what might be described as the ultimate roller coaster ride. Flying on the KC-135 nauseates passengers so frequently, however, that the plane has been nicknamed the "Vomit Comet".
Although best known for its role in astronaut training, about 80 percent of the plane's flights are actually conducted in support of research or engineering. Under a program administered by the Texas Space Grant Consortium, the space agency makes the KC-135 available to undergraduate researchers for two weeks each year. In March of 2000 I traveled to the Johnson Space Center in Houston, where my project team conducted a series of microgravity experiments on board the KC-135. Our project involved the use of virtual reality (VR) as a pre-flight adaptation training tool. Our hope was that advance training in VR would reduce feelings of motion sickness and give trainees a more intuitive understanding of the conditions of zero gravity.
Kate trains in the VR simulator.
A screenshot from the simulator showing the
interior of the KC-135 main cabin.Using Alice, I programmed a VR trainer that simulated the conditions on board the KC-135. We theorized that after someone has practiced a series of simple tasks in the simulator, they would perform the same tasks more effectively in actual practice.
Unfortunately, the sample size in our experiment was too small for the results to be conclusive, but we learned a great deal about the conditions on the plane. We were able to modify the simulator to mirror the conditions more closely, so perhaps it can be used in a future experiment with a larger test group.
I float weightless on the KC-135.
Want to see me fly in zero gravity? Here's a video of Kate, Randy, and I in flight (9 MB).