Sex in space

The conditions governing sex in space (intercourse, conception and procreation while weightless) have become a necessary study due to plans for long-duration space missions, as well as the future potential accommodation of sexual partners aboard the International Space Station (ISS). Issues explored include disrupted circadian rhythms, radiation, isolation, stress, and the physical acts of intercourse in zero or minimal gravity.

Sex in space is a part of space sexology.

Human sexual activity in the weightlessness of outer space presents difficulties due to Newton's third law. According to the law, if the couple remain attached, their movements will counter each other. Consequently, their actions will not change their velocity unless they are affected by another, unattached, object. Some difficulty could occur due to drifting into other objects. If the couple have a combined velocity relative to other objects, collisions could occur. The discussion of sex in space has also raised the issue of conception and pregnancy in space.

As of 2009^[update], with NASA planning lunar outposts and possibly long-duration missions, the topic has taken a respectable place in life sciences. Despite this, some researchers have argued that national and private space agencies have yet to develop any concrete research and plans to address human sexuality in space. Dubé and colleagues (2021) proposed that NASA should embrace the discipline of space sexology by integrating sex research into their Human Research Program. Santaguida and colleagues (2022) have further argued that space agencies and private companies should invest in this discipline to address the potential for sexual harassment and assault in space contexts.

Numerous physiological changes have been noted during spaceflight, many of which may affect sex and procreation, notably circulation and the flow of blood within the body. Such potential effects would likely be caused by a culmination of factors, including gravitational changes, planetary and space radiation, noise, vibration, social isolation, disrupted circadian rhythms, or mental and physical stress.

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 life, evolved under the constant influence of the Earth's 1g gravitational field. It is important to study how space environment affects critical phases of mammalian reproduction and development, as well as the events surrounding fertilization, embryogenesis, pregnancy, birth, postnatal maturation, and parental care.

Studies conducted on rats revealed that, although the fetus developed properly once exposed to normal gravity, rats raised in microgravity lacked the ability to right themselves. Another study examined mouse embryo fertilization in microgravity. Although this resulted in healthy mice, once implanted at normal gravity, the fertilization rate was lower for the embryos fertilized in microgravity. As of 2006^[update], no mice or rats had developed while in microgravity throughout the entire life cycle.

In 2006, American novelist Vanna Bonta invented the 2suit, a garment designed to facilitate sex in weightless environments such as outer space, or on planets with low gravity. The 2suit was made of a lightweight fabric, with a Velcro-lined exterior, which would enable two people to securely embrace. However, Bonta stressed that the 2suit was versatile, and was not intended for the sole purpose of sex. Functionality testing was conducted in 2008 by Bonta aboard G-Force One, a low gravity simulator. It took eight attempts for the two test participants (Bonta and her husband) to embrace one another. According to science author Mark Thompson, the 2suit was cumbersome but moderately successful, and it is not clear whether or not it will have practical value for future space travelers. The 2suit has been covered in the TV series The Universe as well as a 2008 History Channel television documentary. It has also been discussed by online writers.