The flight will originate from NASA’s Kennedy Space Center in Florida. The journey will consist of parabolic trajectories (kinda like rollercoaster rides up and down high peaks and low valleys) at around 9,100 meters (about 5.7 miles) above the Earth’s surface.
A parabola begins when the aircraft begins to climb at about 7,300 meters (24,000 feet) at an angle of about 45 degrees. The airplane reaches its maximum altitude of about 9,750 meters (32,000 feet), at which time the pilot points the airplane’s nose down toward the Earth at an angle of about 30 degrees.
NASA’s Reduced Gravity Research Program has been operating since 1973 to study the effects of weightlessness on astronauts in outer space. The nickname Vomit Comet was applied to the KC-135 airplane that was used to perform 20- to 25-second plunges to experience weightlessness, and oftentimes space sickness. Often, 30 to 60 parabolic trajectories were taken during the experiment.
Today, NASA, for publicity reasons, prefers the name Weightless Wonder over the term Vomit Comet, although the term still permeates test subjects who participate in the medical studies.
The airplane creates weightlessness by flying a parabolic near-vertical flight path upward, leveling off, reducing thrust, and dropping down similar to an object (such as a sky diver) in free fall. Consequently, the people onboard the airplane apparent to have zero apparent weight relative to the aircraft.
This experience sometimes produces nausea similar to airsickness, which is how the airplane got its original nickname. Two KC-135 Stratotankers were used until December 2004 for these NASA studies in motion sickness.
Now, since 2005, NASA uses a McDonnell Douglas C-9B Skytrain II. That same year, Zero-Gravity Corporation began commercial parabolic flight operations very similar to the ones used by NASA. The company provides these services to researchers and tourists, alike, using Boeing 727 jets. Each flight consists of about 15 parabolic cycles to simulate gravity levels on the Moon (one-sixth that of Earth’s gravity) and Mars (about one-third), and to simulate complete weightlessness.
This correspondent has taken two trips onboard NASA’s KC-135 between 1984 and 1985 as part of NASA’s studies with the effects of weightlessness. Preparations for the flights included experiments at the Johnson Space Center, Clear Lake City, Texas (just outside of Houston).
Basically, the ground studies included sitting in a barber-like rotating chair while doing head movements first forward, to the right-side, backwards, and to the left-side. These were repeated while the chair rotated around, and around, and around. Various types of experiments were performed in these barber chairs. Then, once in the Vomit Comet, these same movements were made while in these parabolic trajectories—again, around, and around, and around. (Get the picture!!)
I made it without throwing up. However, I did experience some airsickness as we returned to Ellington Field (just north of the Johnson Space Center) and hit a patch of rough air that jerked the airplane up quickly, and my stomach, too!
A friend of mine also experienced the Vomit Comet near this time. Realizing that he often gets carsick, he was carefully helped off the airplane after his flight and driven home. Rounding the last corner, he threw up out the window, and (I think) was out of work for about two days.
The public relations person for Zero-Gravity Corporation stated that about one-third of its customers have no airsickness, while one-third have minor airsickness and the last one-third are seriously airsick, which is why they probably call the airplane the Vomit Comet rather than the Weightless Wonder.
Good luck Dr. Hawking on your weightless flight!
An earlier ITwire story called “Stephen Hawking going weightless in ‘Vomit Comet’-like airplane ride” appears at: http://www.itwire.com.au/content/view/10078/1066/.
The operational base of Zero Gravity Corporation (often called ZERO-G) is Dania Beach, Florida (south of Fort Lauderdale) and its headquarters is Santa Monica, California. The home Web page of Zero Gravity Corporation is: http://www.gozerog.com/home_full1.aspx.
The home Web page of Professor Steven Hawking is: http://www.hawking.org.uk/home/hindex.html.
The Web page of How Stuff Works explains weightlessness in more detail: http://science.howstuffworks.com/weightlessness.htm.