Sex in space
Sex in space refers to human sexual activity in the weightlessness and/or extreme environments of outer space. The act of human intimacy, sexual intercourse, and procreation distinguished by the state of weightlessness (precluding artificial gravity) presents difficulties surrounding the performance of most sexual activities due to Newton's Third Law. The issue also includes conception and pregnancy in off-Earth environments.
The topic of sex in space has been debated to clarify its potential impact on human beings in the isolated, confined, and hazardous space environment. Past discussions often included attempts to determine the veracity of speculations (e.g., about the STS-47 mission, on which married astronauts Mark C. Lee and Jan Davis flew), and even hoaxes, such as Document 12-571-3570. Experts such as Princeton astrophysics professor Dr. J. Richard Gott consider humanity's expansion into space crucial to survival, but it was considered taboo for decades of spacefaring exploration history.
As of 2009, with NASA planning long-term missions for lunar settlements with goals to explore and colonize space, the topic has taken a respected place in life sciences. Scientist Stephen Hawking publicly concurred in 2007 that possibly human survival itself will depend on successfully contending with the extreme environments of space.
In February 2013, Dennis Tito's Inspiration Mars Foundation announced that they were going to send a two-person crew - a man and a woman - to a 501 days free-return flyby mission to Mars and back. Jane Poynter stressed the importance of the pre-existing stable emotional bond between the members of the couple. She cited her own experience as being a Biosphere 2 crew member together with her husband Taber MacCallum, who is the chief technology officer of Inspiration Mars.
Physiological issues 
Numerous physiological changes have been noted during spaceflight, many of which may affect sex and procreation, although it remains unclear whether such effects are due to gravity changes, radiation, noise, vibration, isolation, disrupted circadian rhythms, stress, or a combination of these factors.
The primary issue to be considered in off-Earth reproduction is the lack of gravitational acceleration. Life on Earth, and thus the reproductive and ontogenetic processes of all extant species and their ancestors, evolved under the constant influence of the Earth's 1G gravitational field. It is imperative to study how space environment affects critical phases of mammalian reproduction and development as well as events surrounding fertilization, embryogenesis, pregnancy, birth, postnatal maturation, and parental care. Gravity affects all aspects of vertebrate development, including cell structure and function, organ system development, and even behavior. As gravity regulates mammalian gene expression then there are significant implications for successful procreation in an extraterrestrial environment.
Studies conducted on reproduction of mammals in microgravity include experiments with rats. Although the fetus developed properly once exposed to normal gravity, the rats that were reared in microgravity lacked the ability to right themselves. Another study examined mouse embryo fertilization in microgravity. Although both groups resulted in healthy mice once implanted at normal gravity, the authors noted that the fertilization rate was lower for the embryos fertilized in microgravity than for those in normal gravity. Currently no mice or rats have developed while in microgravity throughout the entire developmental cycle.
The psychosocial implications of in-flight sex and reproduction are at least as problematic as the related physiological challenges. For the foreseeable future, space crews will be relatively small in number. If pairing off occurs within the crew, it can have ramifications on the crew's working relationships, and therefore, on mission success and crew operations. Behavioral health, close proximity, compatibility and coupling will all be factors determining selection of crews for long term and off-planet missions.
Lyubov Serova, a specialist with the Russian Institute for Biomedical Problems (IBMP) in the field of procreation in the conditions of spaceflight, says "After a period of adaptation for weightlessness, people will not need any special devices, like elastic belts or inflatable tubes to have sex in space," and "We study the impact of weightlessness on the reproductive function of male and female bodies by using mammals as test subjects, particularly rats." The overall conclusion is that sex in space is not a physical problem, and that individuals motivated enough to embark on space flight won't be distracted by sex.
The 2suit (alternately 2-Suit or twosuit) is a garment designed to facilitate effortless intimacy in the weightless environments such as outer space, or on planets with low gravity.The flight garment, invented by Vanna Bonta, was one of the subjects of a television documentary. The 2suit sparked international discussions in blogs, news and political debates as an iconic metaphor for human colonization of space.
Popular culture 
"Sex in Space" was the subject of a History Channel documentary for the series The Universe.  When Apollo 11 astronaut Michael Collins published his autobiography Carrying the Fire in 1974, a contemporary Time Magazine quoted the following passage: "Imagine a spacecraft of the future, with a crew of a thousand ladies, off for Alpha Centauri, with 2,000 breasts bobbing beautifully and quivering delightfully in response to every weightless movement . . . and I am the commander of the craft, and it is Saturday morning and time for inspection, naturally". The magazine followed this up by running a letter from one Sharon Smith, who agreed that the presence of breasts "bobbing weightlessly" would render spacemen unable to do their jobs and added that the space program must safeguard itself by the painful but necessary step of excluding men.
The difficulties microgravity poses for human intimacy were discussed in the anonymous fictional NASA Document 12-571-3570 in 1989, where the use of an elastic belt and an inflatable tunnel were proposed as solutions to these problems. A spoof mission patch and other documents were determined to be hoaxes.
The issue of sex in space also appears in a number of science fiction works. In 1973, Isaac Asimov conjectured what sex would be like in the weightless environment of space. He anticipated some of the benefits of engaging in sex in an environment of microgravity. Arthur C. Clarke in turn was quick to point out in a letter to the editor that he had beaten Collins to addressing the matter in the novel Rendezvous with Rama (1973): "Some women, Commander Norton had decided long ago, should not be allowed aboard ship; weightlessness did things to their breasts that were too damn distracting. It was bad enough when they were motionless; but when they started to move, and sympathetic vibrations set in, it was more than any warm-blooded male should be asked to take. He was quite sure that at least one serious space accident had been caused by acute crew distraction, after the transit of an unholstered lady officer through the control cabin."
A more recent and perhaps more realistic description of the mechanics of low-gravity intercourse is presented in "Sex in Space: The Video," a short story contained in Susie Bright's "The Best American Erotica 2004." The story uses cheating astronauts to describe techniques humans might use to copulate in space without special apparatus.
Among the films, which include space sex themes, are Moonraker, Moving Violations, Supernova, The Uranus Experiment and Cube 2: Hypercube. In the novelization of Alien, Parker tells Brett about an episode of zero-G sex that went wrong. The adult entertainment production company Private Media Group has filmed a movie called The Uranus Experiment: Part Two where the zero gravity intercourse scene was accomplished by flying an airplane to an altitude of 11,000 feet (3350 meters) and then doing a steep dive. The filming process was particularly difficult from a technical and logistical standpoint. Budget constraints allowed only for one 20 second shot, featuring the actors Sylvia Saint and Nick Lang. Berth Milton, Jr, president and CEO of Private Media Group says "You would not want to be afraid of flying, that's for sure!" The soundtrack was produced by 3D from Massive Attack and Liam from The Prodigy.
See also 
- Effect of spaceflight on the human body
- Reproduction and pregnancy in speculative fiction
- Space advocacy
- Space colonization
- Space medicine
- Space tourism
- Mile high club
- Thrusters on full: Sex in space, By Keiron Monks, Metro World News; 10 April 2012
- Outerspace sex carries complications by Alan Boyle, Science editor MSNBC 24 July 2006
- Seks in de ruimte: is het mogelijk?, By Caroline Hoek; 7 April 2012
- S’envoyer en l’air dans l’espace Par Kieron Monks, Metro World News; 11 Avril 2012
- wayne (29 September 2008). "J. Richard Gott - Space Colonization Imperative". Idea Festival. Retrieved January 2009.
- The Universe: Sex in Space Explores Human Side of Space, by Darpana Kutty; Top News India 02 Dec. 2008
- The Universe: Sex in Space Marks New Era For Mankind; History Channel, Dec 2008
- Hui, Sylvia (13 June 2006). "Hawking Says Humans Must Colonize Space". Space.com/Associated Press. Retrieved january 2009.
- The importance of sex in space Cosmos, the science of everything; May 20, 2012
- Jennings RT, Santy PA. Reproduction in the space environment: Part II. Concerns for human reproduction. Obstet Gynecol Surv. 1990;45:7-17
- Ronca AE. Mammalian development in space. Adv Space Biol Med. 2003;9:217-251
- Wakayama S, Kawahara Y, Li C, Yamagata K, Yuge L, T Wakayama (2009). "Detrimental Effects of Microgravity on Mouse Preimplantation Development In Vitro". In Dey, Sudhansu Kumar. PLOS One 4 (8): e6753. Bibcode:2009PLoSO...4.6753W. doi:10.1371/journal.pone.0006753. PMC 2727478. PMID 19707597.
- Gallagher B. No Space Sex? Scientific American. 2000;282:22.
- Harrison AA. Spacefaring: The Human Dimension. Los Angeles: University of California Press; 2001
- space.com - Sex In Space: From Russia...with Love, 2000-03-16
- Vanna Bonta Talks Sex In Space, Celebrity Interview Femail Magazine, 19 August 2012
- Outerspace sex carries complications by Alan Boyle, Science editor MSNBC 24 July 2006
- Spaced out on sex; The Times of India, 26 Jul 2006
- History Channel's The Universe "Sex in Space"
- History Channel to air special on 'sex in space' New Scientist December 17, 2008
- Celebrate Sputnik Day by Thinking About Space Sex, by Audrey Ference - The L Magazine; October 4, 2012
- The History Channel
- The Universe: Sex in Space Marks New Era For Mankind? Dec. 1, 2008
- La fantasía del sexo en gravedad cero PERU21; 29 August 2012
- Sherrod, Robert (1974-08-19). "Lunar Caustic". Time. Retrieved 2008-08-17.
- Smith, Sharon (1974-10-07). "Letters to the Editor". Time.
- Asimov, Isaac (January 1973). Sex in a Spaceship. Sexology Magazine. (Reprinted in Science Past – Science Future, 1975)
- Clarke, Arthur C. (1974-09-23). "Letters to the Editor". Time.
- space.com - Zero Gravity Sex Film Up for Award, 2000-05-16
- space.com - 'To Boldly Go': Star Trek, Sex and Space, 2000-05-16
- How to Have Sex on Other Planets, by Dolan Morgan; ECLECTICA Magazine, October 2011
- Adventures in Space, The Zero-G Spot, by Michael Behar; OUTSIDE Magazine, December 2006
- Outer-space sex carries complications By Alan Boyle, MSNBC July 24, 2006. Concept of "2suit" design of American writer Vanna Bonta.
- Space sex hoax rises again by James Oberg
- Pregnancy in Space Seems Possible
- Astronauts test sex in space - but did the earth move? The Guardian February 24, 2000
- Virgin Galactic rejects $1 million space porn by Peter B. de Selding, MSNBC October 2, 2008.
- Has anyone ever had sex in space? from The Straight Dope by Cecil Adams, 28 February 1997.
- Space Frontier Foundation's media archives for the SFF1484 panel "Sex in Space" from the 2006 "New Space Return to the Moon Conference" featuring authors Laura Woodmansee, and Vanna Bonta with NASA physician Dr. John Logan.
- Inspiration Mars