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Reduced-gravity aircraft

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Trajectory for zero gravity maneuver
Project Mercuryastronautson board aC-131 Samaritanflying as the "vomit comet" in 1959
KC-135 0-G aircraft nicknamed "Vomit Comet"
PhysicistStephen Hawkingon board a reduced-gravity aircraft in April 2007

Areduced-gravity aircraftis a type offixed-wing aircraftthat provides brief near-weightless environments for trainingastronauts,conducting research, and making gravity-free movie shots.

Versions of such airplanes were operated by theNASAReduced Gravity Research Program,[1]and one is currently operated by the Human Spaceflight and Robotic Exploration Programmes of the European Space Agency. The unofficial nickname "vomit comet"became popular among those who experienced their operation.[2]

History

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Parabolic flight as a way of simulating weightlessness was first proposed by the German aerospace engineer Fritz Haber and his brother, physicistHeinz Haberin 1950.[3]Both had been brought to the US afterWorld War IIas part ofOperation Paperclip.[4]As well,Shih-Chun Wangstudied nausea in astronauts forNASA,which helped lead to the creation of the vomit comet.[5]

Parabolic flights are sometimes used to examine the effects of weightlessness on a living organism. While humans are by far the most common passengers, non-human animals have occasionally been involved in experiments, including a notable experiment on how weightlessness affected adomestic cat'srighting reflex[6]and apigeon's attempts to navigate in a weightless state.[7]

Operating principles

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The aircraft gives its occupants the sensation of weightlessness by following aparabolicflight path relative to the center of the Earth.[8]While following this path, the aircraft and its payload are infree fallat certain points of its flight path. The aircraft is used in this way to demonstrate to astronauts what it is like toorbitthe Earth. During this time the aircraft does not exert anyground reaction forceon its contents, causing the sensation of weightlessness.

Initially, the aircraft climbs with a pitch angle of 45 degrees using engine thrust and elevator controls. The sensation of weightlessness is achieved by reducing thrust and lowering the nose to maintain a neutral, or "zero lift", configuration such that the aircraft follows a ballistic trajectory, with engine thrust exactly compensating for drag. Weightlessness begins while ascending and lasts all the way "up-and-over the hump", until the craft reaches a downward pitch angle of around 30 degrees. At this point, the craft is pointing downward at high speed and must begin to pull back into the nose-up attitude to repeat the maneuver. 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 reduces the thrust and lowers the nose.[9]

This aircraft is used to train astronauts in zero-g maneuvers, giving them about 25 seconds of weightlessness out of 65 seconds of flight in eachparabola.During such training, the airplane typically flies about 40–60 parabolic maneuvers. In about two thirds of the passengers, these flights producenauseadue toairsickness,[10][11]giving the plane its nickname "vomit comet".

Parabolicfree fall trajectories near Earth (or other massive objects) lead from infinity to the lowest point and then away back to infinity (assuming there are no other massive objects like the Sun). A (small) object like a rock following such a trajectory would accelerate as it falls down, reaching its highest speed at the lowest point, miss Earth, and then fall back up to infinity, slowing down. The speed on a parabolic trajectory is calledescape speed,which is greatest at the lowest point (~11,2 km/s for a near Earth flyby). At lower speeds the trajectory is anellipsewhere the slowest speed is at the highest point. Aircraft can not fly at 11.2 km/s to follow parabolic free fall trajectories, but they can follow suborbital elliptic trajectories at lower speeds such as 0.1 km/s and also experience weightlessness that way. These flights are often called parabolic flights because on a small scale Earth is flat and gravity doesn't change significantly, so trajectories are nearly parabolic. But because Earth is round, the direction of gravity changes, so slow trajectories are elliptic. Local changes in density (mountains, water) causedistortions in gravityand distort trajectories from pure parabolas and ellipses, possibly more than the small difference between the relevant sections of ellipses and parabolas.

Operators

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Canada

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TheCanadian Space Agencyand theNational Research Councilhave aFalcon 20used for microgravity research.[12]The small plane is normally not used for people to float freely and experience weightlessness; however, comedianRick Mercerdid so for a segment of hisshow.[13]

Ecuador

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Ecuadorian crew in weightlessness.

The first zero G plane to enter service in Latin America is aT-39 SabrelinernicknamedCONDOR,operated for theEcuadorian Civilian Space Agencyand theEcuadorian Air Forcesince May 2008.[14]On June 19, 2008, this plane carried a seven-year-old boy, setting the Guinness world record for the youngest person to fly in microgravity.[15]

Europe

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Since 1984,ESAand theCNEShave flown reduced-gravity missions in a variety of aircraft, including NASA's KC-135, aCaravelle,anIlyushin Il-76MDK,and anAirbus A300known as theZero-G.In 2014 the A300 was phased out in favor of a more modernAirbus A310,also namedZero-G.[16]It is based atBordeaux-Mérignac airportinFrance,operated by Novespace, and has also been flown fromParis Le Bourget airportandDübendorf Air Basein Switzerland.[17]Since 1997 CNES subsidiary Novespace has handled the management of these flights.[18]

ThisA310 Zero G[fr]aircraft is used also to realize commercial flights for public passengers in partnership between operator Novespace and theAvico[fr]company, under Air Zero G brand.[19]The aircraft has also been used for cinema purposes, withTom CruiseandAnnabelle Wallisfilming forThe Mummyin 2017.[20]

Russia

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In Russia, commercial flights are offered on theIlyushin Il-76MDKjet; several U.S. companies book flights on these jets.[21]

TheIndian Air forcealso used them to train the first batch of Indian Astronauts for theGaganyaan ProjectofISRO.[22]

United States

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Peter DiamandisofZero Gravity Corporation

NASA

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A300-Zero-G.

NASA flew zero gravity flights on various aircraft for many years. In 1959Project Mercuryastronauts trained in aC-131 Samaritanaircraft dubbed the "vomit comet".[23]

TwinKC-135 Stratotankerswere used until December 2004 and later retired. One, a KC-135A registered N930NA (also known as NASA 930, formerly USAF serial no. 59-1481), flew more than 58,000 parabolas after NASA acquired it in 1973, before being retired in 1995. It is now on display atEllington Field,near theJohnson Space Center.The other (N931NA or NASA 931, formerly AF serial no. 63-7998) was also used byUniversal PicturesandImagine Entertainmentfor filming scenes involving weightlessness in the movieApollo 13;it made its final flight on October 29, 2004, and is permanently stored in thePima Air & Space Museumin Tucson, Arizona.

In 2005 NASA replaced these aircraft with aMcDonnell DouglasC-9B Skytrain II(N932NA) formerly owned byKLM Royal Dutch Airlinesand theUnited States Navy.[24]

NASA concluded the Reduced Gravity Research Program and ended operations in July 2014, due to aircraft technical problems. It is replaced with private company contracts.

As of 2015NASA had a microgravity services contract withZero Gravity Corporation(ZERO-G) and used its aircraft, G-FORCE ONE, a modified Boeing727-200.[25]

Other operators

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In late 2004, theZero Gravity Corporationbecame the first company in the United States to offer zero-g flights to the general public, usingBoeing 727jets. Each flight consists of around 15 parabolas, including simulations of the gravity levels of the Moon and Mars, as well as complete weightlessness.[26]This profile allows ZERO-G's clients to enjoy weightlessness with minimal motion discomfort.

In 2015,Integrated Spaceflight Services,began serving as the research and education integrator of theNational Research Council of Canadafor the US market, offering comprehensive reduced-gravity services on a modifiedFalcon 20aircraft.[27]ISS has flown annual microgravity research campaigns to evaluate space suits and other technologies withProject PoSSUM.[28]

Aurora AerospaceinOldsmar, Floridaoffers zero-g flights using aFuji/Rockwell Commander 700.It is also used to simulate the gravity of the Moon and Mars.[29]

Airsickness

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According to former Reduced Gravity Research Program director John Yaniec, anxiety contributes most to passengers' airsickness. The stress on their bodies creates a sense of panic and therefore causes the passenger to vomit. Yaniec gives a rough estimate of passengers, that "one third [become] violently ill, the next third moderately ill, and the final third not at all." Vomiting is referred to as being "ill".[10]

Scopolamineis often used as anantiemeticduring reduced-gravity-aircraft training.[30]

Use in media production

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The 1995 filmApollo 13filmed many scenes aboard NASA's KC-135 parabolic aircraft.

In 2016, rock groupOK Gorecorded a music video for their single "Upside Down & Inside Out"on a reduced-gravity aircraft, which involved acrobatic choreography created specifically for the zero-gravity environment.[31]

The adult entertainment production companyPrivate Media Grouphas filmed apornographicmovie calledThe Uranus Experiment: Part Twowhere a zero-gravity intercourse scene was filmed aboard a reduced-gravity aircraft. The filming process was particularly difficult from a technical and logistical standpoint. Budget constraints allowed for only one20-secondshot, featuring the actorsSylvia Saintand Nick Lang.[32]Berth Milton, Jr,president andCEOof Private Media Group, said in 2000 "You would not want to be afraid of flying, that's for sure!"[33]

The ZERO-G corporation was featured in theMythBustersNASA Moon Landing Conspiracy episode, in which it flewAdam SavageandJamie Hynemanon a custom flight path to replicate the Moon's gravity. This allowed Savage to replicate the footage ofNeil Armstrongwalking on the Moon, disarming claims that the footage was forged.

See also

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References

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  1. ^"NASA Reduced Gravity Research Program".Jsc-aircraft-ops.jsc.nasa.gov. 2009-03-17. Archived fromthe originalon 2009-08-25.Retrieved2009-09-14.
  2. ^"NASA - What's the Vomit Comet?".Archived fromthe originalon May 5, 2012.RetrievedMay 15,2012.
  3. ^Haber, Fritz; Haber, Heinz (1950). "Possible methods of producing the gravity-free state for medical research".Journal of Aviation Medicine.21(5): 395–400.PMID14778792.Summary of the article:Campbell, Mark R. (2009). "Classics in space medicine. Possible methods of producing the gravity-free state for medical research".Aviation, Space, and Environmental Medicine.80(12): 1077.doi:10.3357/ASEM.26010.2009.PMID20027862.
  4. ^Burkhard, Ford (1998-08-28)."Fritz Haber, 86, Dies; Simulated Weightlessness of Space".New York Times.
  5. ^"New chancellor took her own path | News".news-gazette. 2011-10-16.Retrieved2020-02-16.
  6. ^"Weightless Cats - Do Space Cats Land On Their Feet?".YouTube. 2011-01-11.Retrieved2020-02-16.
  7. ^"Pigeons In Space".YouTube. 2011-02-04.Retrieved2020-02-16.
  8. ^William Tyrrell Thomson, Introduction to Space Dynamics, Dover 1986. p. 91.
  9. ^"C-9B Flight Trajectory".Jsc-aircraft-ops.jsc.nasa.gov. 2009-03-17. Archived fromthe originalon 2009-12-13.Retrieved2009-09-14.
  10. ^abGolightly, Glen (October 20, 1999)."Flying The Vomit Comet Has Its Ups And Downs".space. Archived fromthe originalon 2006-03-10.
  11. ^"Reduced Gravity: Vomit Comet Blog".PhysicsCentral.May 10, 2005.Retrieved2007-11-07.
  12. ^"Falcon 20 - Facilities - NRC-CNRC".Archived fromthe originalon June 11, 2011.RetrievedJune 26,2009.
  13. ^"RMR: Rick and Zero Gravity".YouTube. 2011-06-16.Retrieved2016-02-24.
  14. ^"Exa And Fae Develops First Zero-G Plane In Latin America".Exa.ec. 2008-04-10.Retrieved2009-09-14.
  15. ^"Youngest person to experience microgravity".Guinnessworldrecords.Retrieved2009-09-14.
  16. ^"Air Zero-G About Us".airzerog.Retrieved2014-03-11.
  17. ^"ESA's A300 Zero-G Program"(in Dutch). Spaceflight.esa.int. Archived fromthe originalon 2009-08-28.Retrieved2009-09-14.
  18. ^"CNES: PR56-2004 - New parabolic flight campaign".Archived fromthe originalon June 27, 2009.RetrievedOctober 4,2008.
  19. ^"French astronaut performs" Moonwalk "on parabolic flight - Air & Cosmos - International".Air & Cosmos - International.Retrieved2017-08-29.
  20. ^"'The Mummy': Behind the Scenes of That Zero-G Stunt (Exclusive) ".The Hollywood Reporter.Retrieved2017-08-29.
  21. ^"Zero-gravity flights go mainstream - Technology & science - Space".NBC News.2004-09-16. Archived fromthe originalon August 29, 2014.Retrieved2016-02-24.
  22. ^Sharma, Ritu (2024-03-04)."From Fighter Pilots To Astronauts – How IL-76 Aircraft Helped India Train Its 'Vyomnauts' For 1st Manned Space Mission".Latest Asian, Middle-East, EurAsian, Indian News.Retrieved2024-05-21.
  23. ^"Mercury Astronauts in Weightless Flight on C-131 Aircraft".2006-08-02. Archived fromthe originalon 2015-02-14.Retrieved2013-05-14..Page hosts a NASA photograph dated 01/01/1959.
  24. ^"C-9B History".NASA.Archived fromthe originalon 2009-12-15.Retrieved2009-09-14.
  25. ^"Flight Opportunities program".NASA.Retrieved2013-04-22.
  26. ^Boyle, Alan (2004-09-16)."Zero-gravity flights go mainstream".NBC News. Archived fromthe originalon August 29, 2014.Retrieved2009-09-14.
  27. ^"Integrated Spaceflight Services".Integratedspaceflight.Retrieved2015-04-06.[permanent dead link]
  28. ^"Private Spacesuit Undergoes Zero-G Testing to Prepare for Commercial Flight".2017-11-20.Retrieved2020-08-07.
  29. ^"Our Training Programs".Aurora Aerospace.Archived fromthe originalon 2009-01-30.
  30. ^Phipps, WS; Yin, Z; Bae, C; Sharpe, JZ; Bishara, AM; Nelson, ES; Weaver, AS; Brown, D; McKay, TL; Griffin, D; Chan, EY (2014)."Reduced-gravity Environment Hardware Demonstrations of a Prototype Miniaturized Flow Cytometer and Companion Microfluidic Mi xing Technology".J Vis Exp(93): e51743.doi:10.3791/51743.PMC4354048.PMID25490614.
  31. ^Allain, Rhett (February 12, 2016)."The Physics of OK Go's Epic New Zero-G Video".Wired.ISSN1059-1028.Retrieved2021-07-23.
  32. ^"Zero Gravity Sex Film Up for Award".SPACE.16 May 2000. Archived fromthe originalon 20 June 2000.Retrieved25 January2014.
  33. ^"'To Boldly Go': Star Trek, Sex and Space ".SPACE.16 May 2000. Archived fromthe originalon 6 July 2008.

Further reading

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