Vomit Comet

"Vomit Comet" is a nickname for any airplane that briefly provides a nearly weightless environment in which to train astronauts, conduct research, and film motion pictures.Versions of such airplanes have in the past been operated by NASA's [http://jsc-aircraft-ops.jsc.nasa.gov/Reduced_Gravity/index.html Reduced Gravity Research Program] since 1973, where the unofficial nickname originated. NASA then adopted the official nickname Weightless Wonder, for publication. [ [http://www.nasaexplores.com/show2_articlea.php?id=03-008 NASA "Weightless Wonder"] ]

Operating principles

The airplane produces weightlessness by following a parabolic vertical flight path. A parabolic flight path is the same path that would be taken by an object in free fall, such as a cannonball fired into the air. As a result, the aircraft does not exert any g-force on its contents, so the contents have zero apparent weight relative to the aircraft.

The aircraft heads upward at an angle of 45 degrees. As soon as the pilot begins the rotation into the parabolic trajectory, weightlessness is achieved. This lasts all the way "up-and-over the hump", until the craft reaches a declined angle of 30 degrees. At this point, the craft has lost a significant amount of altitude, and must begin to pull into a hard upward turn. The forces are then roughly twice that of gravity on the way down, at the bottom, and up again. This lasts all the way until the aircraft is again halfway up its upward trajectory, and the pilot again initiates the zero-g parabola. [ [http://jsc-aircraft-ops.jsc.nasa.gov/Reduced_Gravity/trajectory.html C-9B Flight Trajectory] ]

In general, this aircraft is used to train astronauts in zero-g maneuvers, giving them about 25 seconds of weightlessness out of 65 seconds of flight. This often produces nausea due to airsickness, especially in novices, giving the plane its nickname.

History

NASA has flown parabolic flights on various aircraft for many years. In 1959, Project Mercury astronauts trained in a C-131 Samaritan aircraft, which was dubbed the "Vomit Comet".Citation
last =von Ofenheim
first =Bill
title =Mercury Astronauts in Weightless Flight on C-131 Aircraft
date =2004-01-20
url =http://nix.larc.nasa.gov/info;jsessionid=2oo6qenn8gdvf?id=GPN-2002-000039&orgid=12
accessdate =2007-09-03 Page hosts a NASA photograph dated 01.01.1959, which is also at . ]

Twin KC-135 Stratotankers were used until December 2004 and have since been retired. One, a KC-135A known as NASA 930, was also used by Universal Pictures and Imagine Entertainment for filming scenes involving weightlessness in the movie "Apollo 13"; that airplane was retired in 2000 and is now on display at Ellington Field, near the Johnson Space Center. It is estimated to have flown over 58,000 parabolas. The other (N931NA or NASA 931) made its final flight on October 29, 2004, and is permanently stored in the Pima Air & Space Museum in Tucson, Arizona.

In 2005, NASA replaced the airplane with a McDonnell Douglas C-9B Skytrain II that was formerly owned by KLM Royal Dutch Airlines and the United States Navy [http://jsc-aircraft-ops.jsc.nasa.gov/Reduced_Gravity/C_9B_history.html] . That same year, the Zero-Gravity Corporation, a commercial parabolic flight operator which offers parabolic flights to both researchers and adventure tourists, began flying parabolic flights for NASA with Boeing 727 jets.

Since 1984, the ESA and the CNES have flown similar reduced-gravity missions in a variety of airplanes, including NASA's KC-135, a Caravelle, an Ilyushin IL-76 MDK, and, most recently, an Airbus A300 known as the "Zero-G", which is flown out of the Bordeaux-Mérignac airport in France. [ [http://www.spaceflight.esa.int/users/index.cfm?act=default.page&level=11&page=paraf ESA's A300 Zero-G Program] ]

Commercial flights

In late 2004, Zero Gravity Corporation became the first and only company in the United States to offer parabolic weightlessness flights to the general public. Each flight consists of around 15 parabolas, including simulations of the gravity levels of the Moon and Mars, as well as complete weightlessness. [ [http://www.msnbc.msn.com/id/5992077/ MSNBC article] ]

Latin America's first zero G plane

The first zero G plane in Latin America is a T-39 Sabreliner nicknamed "CONDOR", operated by the Ecuadorian space agency and the Ecuadorian Air Force. It has operated since May, 2008. [http://exa.ec/bp16/index-en.html EXA AND FAE DEVELOPS FIRST ZERO-G PLANE IN LATIN AMERICA] ] On June 19 2008, this plane carried 7 year old Jules Nader as he set the Guinness world record for the youngest human being flying in microgravity. Nader worked on an hydrodynamics experiment designed by his brother. [http://www.guinnessworldrecords.com/adjudications/080623_Youngest_Person_Microgravity.aspx Youngest person to experience microgravity] ]

Airsickness

According to former Reduced Gravity Research Program director John Yaniec, anxiety contributes most to passengers' airsickness. Yaniec gives a rough estimate that of passengers, "one third [become] violently ill, the next third moderately ill, and the final third not at all." Vomiting is referred to as a "kill". [cite web
url = http://www.physicscentral.com/freefall/blog/051006.html
title = Reduced Gravity: Vomit Comet Blog
accessdate = 2007-11-07
date= May 10, 2005
work = PhysicsCentral]

Commercial operator Zero Gravity Corporation claims their tourist rides with up to 15 parabolas are much less traumatic compared to the typical research flight with 40–80 parabolas. [Zero G corp FAQ on motion [http://www.gozerog.com/FAQ.htm#sickness sickness] ]

Other uses of the term

"Vomit comet" may also refer to any other form of transportation on which riders are said to become nauseated or seasick, such as a bus that transports late-night revelers [ [http://www.doubletongued.org/index.php/dictionary/vomit_comet Double-Tongued Dictionary entry] ] [All night TTC [http://www.citynews.ca/news/news_3737.aspx bus] ] or a fast boat such as a high-speed catamaran. [ [http://www.thestar.com/printArticle/179218 Key West ferry] ] . [ [http://www.isle-of-wight.net/ Isle of Wight Ferry] ]

ee also

* Microgravity
* Space tourism

Notes

References

* Haber, Fritz and Haber, Heinz: "Possible Methods of Producing the Gravity-Free State for Medical Research", "Journal of Aviation Medicine" XXI (1950)
* Easton, Pam (October 30, 2004). [http://www.chron.com/cs/CDA/ssistory.mpl/metropolitan/2873672 NASA's weightless aircraft is retired] . Associated Press.
* Golightly, Glen (May 15, 2000). [http://www.space.com/news/spaceagencies/comet_retired_000515.html Vomit Comet finds a home] . Space.com Houston Bureau.
* Overbye, Dennis (March 1, 2007), "Stephen Hawking [http://www.nytimes.com/2007/03/01/science/01hawking.html plans prelude] to the ride of his life", "New York Times"

External links

* [http://jsc-aircraft-ops.jsc.nasa.gov/Reduced_Gravity/index.html Reduced Gravity Research Program]
* [http://www.space.com/peopleinterviews/yaniec_991020.html Interview with John Yaniec]
* [http://microgravity.grc.nasa.gov/ground/aircraft.htm About the NASA Reduced Gravity Research Program]
* [http://www.atlasaerospace.net/eng/zgrav.htm ATLAS aerospace is a Russian company that offers reduced gravity flights in an IL-76 MDK wide-body airplane.]
* [http://www.olivierpascaud.com/zerogravity Virtual tour of the Airbus A-300 Zero-G]
* [http://www.clubhyper.com/reference/c135jh_6.htm C-135 Variants Part 6 - includes scale drawing of NASA 930]
* [http://stuff.mit.edu/people/powell/fas_adv.html Reduced Gravity Experiment in a Nasa´s KC-135A]