Sex in Space
H.G. Stratmann
Introductory Remarks
• The focus of this talk will be on the “classic”
combination of one adult male and one adult
female.
• The effects of the space environment on other
combinations of numbers/genders can be
extrapolated from the information presented
here.
The History of Mixed-Gender Human Spaceflight
• Vostok 1 April 12, 1961 One-man orbital
flight
• Mercury-Redstone 3 May 5, 1961 One-man
suborbital flight
• Mercury-Redstone 4 July 21, 1961 One-man
suborbital flight
• Vostok 2 August 6, 1961 One-man orbital
flight
The History of Mixed-Gender Human Spaceflight
• Mercury-Atlas 6 February 20, 1962 One-man
orbital flight
• Mercury-Atlas 7 May 24, 1962 One-man
orbital flight
• Vostok 3 August 11, 1962 One-man orbital
flight
• Vostok 4 August 12, 1962 One-man orbital
flight
The History of Mixed-Gender Human Spaceflight
• Mercury-Atlas 8 October 3, 1962 One-man
orbital flight
• Mercury-Atlas 9 May 15, 1963 One-man
orbital flight
• The first time a man and woman flew in space
was in June 1963
The History of Mixed-Gender Human Spaceflight
• The first woman in space was cosmonaut
Valentina Tereshkova, aged 26 at the time of her
flight
• She and her fellow, male cosmonaut Valery
Bykovsky, aged 29, flew in space at the same time
• However, any inclination toward intimate
interpersonal relations between these two
cosmonauts would not have been technically
feasible
The History of Mixed-Gender Human Spaceflight
• Valery Bykovsky occupied a one-person
capsule in orbit (Vostok 5, June 14-19, 1963)
• Valentina Tereshkova occupied a second oneperson capsule in orbit (Vostok 6, June 16-19,
1963)
• The two capsules did not allow docking
maneuvers of any kind to be performed
The History of Mixed-Gender Human Spaceflight
• All subsequent spaceflights during the 1960s
and 1970s were made only by men
• The initial space stations placed in orbit,
Skylab (1973) and the first 6 Salyut stations,
also had all-male crews
• The first “co-ed” crew in orbit together within
touching distance was on Salyut 7
The History of Mixed-Gender Human Spaceflight
• A three-person crew consisting of the second
woman in space, Svetlana Savitskaya (age 34),
and two male cosmonauts flew to orbit in a Soyuz
capsule (August 1982)
• They stayed aboard Salyut 7 together for several
days
• Savitskaya made a second flight to Salyut 7 with
two different male cosmonauts in July 1984,
where she became the first woman to make a
spacewalk
The History of Mixed-Gender Human Spaceflight
• The third woman to reach space was Sally Ride
aboard Challenger (ST-7) in 1983, as part of a fiveperson crew
• Since then mixed-gender crews on the Space Shuttle
and space stations (Mir and the ISS) have been
common
• There is the potential for husband-wife teams to fly
into space together
– STS-47 (1992) included a husband-wife team, Mark Lee
and Jan Davis
The History of Mixed-Gender Human Spaceflight
• Question: Has sexual activity been performed
by humans in space?
• Answer: Who knows? There has been no
official confirmation.
• The only people who know for sure
apparently aren’t telling.
• NASA appears to have the equivalent of a
“Don’t ask, don’t tell” policy.
Sex in Space?
• Question: In theory, could sex be performed in
space?
• Answer: Yes, but it could be difficult and even
dangerous due to problems with:
 Microgravity and its effects on human
anatomy and physiology
 Radiation in space
 Psychological effects of the space
environment
Review of Basic Sexual Physiology
• Women:
– Cerebral and peripheral (e.g. the pudenal nerves
and sacral plexus) pathways leading to and from
the spinal cord are activated by:
• Psychic stimulation (e.g. thinking erotic thoughts)
• Local stimulation of the genitalia and other sensitive
body parts
– Parasympathetic nerves act by:
• Dilating the arteries of erectile tissue
• Stimulating secretion of mucus that acts as a lubricant
for coitus
• Relaxing smooth muscles
Review of Basic Sexual Physiology
• Women:
– Climax is achieved via the sympathetic nervous
system and spinal cord reflexes
– Men also achieve climax by means of the
sympathetic nervous system
Review of Basic Sexual Physiology
• Men:
– Performance and completion of coitus is
dependent on achieving and maintaining penile
erection
– As with women, physical and psychic stimulation
play important roles in production of an erection
– These types of stimulation activate the
parasympathetic nervous system
– Nerve impulses transmitted from the sacral spinal
cord pass through the pelvic nerves to the penis
Review of Basic Sexual Physiology
• Men:
– Nerve impulses cause relaxation of penile arteries
(thereby increasing blood flow) and the smooth
muscle in its erectile tissue
– This erectile tissue consists of large cavernous
sinusoids that are normally nearly empty of blood
– These sinusoids dilate tremendously when arterial
blood flows into them under pressure and venous
outflow is partially occluded
Review of Basic Sexual Physiology
• Men:
– The erectile tissue is surrounded by strong fibrous
tissue
– The combined effects of these changes in blood
flow and presence of this fibrous tissue produces
the characteristic hardening, elongation, and
elevation of the penis
– Stimulation of the penis produces climax
• As in women, reflexes involving the sympathetic
nervous system are required for climax
Why Space is a Terrible Place for Sex
• Some space travelers might find the thought
of “doing it” in space psychologically
stimulating
• This enthusiasm may be strongly curbed by
other physiological and psychological effects
of being in space
“Not tonight dear, I have Space Adaptation
Syndrome”
• Space Adaptation Syndrome occurs in about twothirds of trained space travelers within minutes to
about 2 hours after entering space and may persist
for up to about a week
• Occurs in about 85% of less well-trained space
travelers (e.g. space tourists?)
• Headache, nasal congestion, dizziness, nausea, and
vomiting (typically without warning) can occur,
potentially reducing desire for sexual activity
(It’s hard to feel sexy when you’re upchucking all over
yourself and your partner)
Impediments to Sex in Space
• Anxiety, overexcitement, busy work schedules,
and lack of privacy may also inhibit
performance
• Adverse physiological effects of microgravity:
– Male rats on Cosmos 2044 had a fall of
testosterone levels to < 20% of controls while in
space
– Comparable effects in human males would likely
inhibit sexual function
Impediments to Sex in Space
• Other adverse physiological effects of
microgravity:
– Mild anemia
– Loss of about one to two liters of fluid from the
body
– Reduced tone in the autonomic nervous system,
particularly its sympathetic component
– All of these factors could have a deflating effect on
erectile function
Impediments to Sex in Space
• Still other adverse physiological effects of
microgravity:
– Prolonged exposure to microgravity produces
reduction of bone and muscle mass to about 85%
of baseline, despite vigorous exercise
– Depending on the circumstances, performing sex
may require significantly more energy and be
associated with increased risk of fractures (of one
type or another) in the event of an “accident”
Other adverse physiological effects of
microgravity
• Normal energy expenditure and risks of sex:
– Initial performance of intercourse requires at least 2
to 3 METs
• One MET ( metabolic equivalent) is the amount of oxygen a
healthy person uses while sitting quietly (3.5 ml of
oxygen/minute/kilogram of body weight)
– At climax, energy expenditure increases to up to 4
METs (equivalent to walking 3 to 4 miles/hour)
– These energy estimates are based on “ideal”
conditions, with a familiar partner and in familiar
surroundings
Other adverse physiological effects of
microgravity
• Normal energy expenditure and risks of sex:
– In healthy individuals
• Heart rate typically rises to around 130 beats/minute
• Systolic blood pressure typically rises to around 170 to
180 mmHg
– In a stressful environment and with an unfamiliar
(and particularly much younger) partner:
• Peak energy expenditure may rise to 5 to 6 METs or
higher
• Heart rate and systolic blood pressure may rise
significantly above usual maximums
Other adverse physiological effects of
microgravity
• The deconditioning, fluid shifts, and loss of
autonomic tone associated with microgravity may
further increase energy expenditure, heart rate,
and blood pressure during intercourse
• Risk of a myocardial infarction (heart attack) or
death during sex is about 1 to 2 out of a million
• The potential increased risk of this in microgravity
is unknown
Other physiological effects of microgravity
• Astronauts are currently screened for STDs
prior to flight
• Guidelines for future “space tourists” (e.g. at
orbiting “hotels”) regarding screening for STDs
or overall health assessment are uncertain
• Microgravity induces at least a mild reduction
in immune function, thus potentially
increasing the risk of acquiring an STD from an
affected partner in space
Adverse Physical Effects of
Microgravity on Sex
• “Free-floating” sex is rendered dangerous by
Newton’s Third Law of Motion (“For every
action…”)
• Thrusting or other body motions could result in a
coupled couple ricocheting off a wall, striking
one’s head or other sensitive body part, or worse
• Mistimed motions might also lead to
“decoupling” and the separated partners
shooting away in opposite directions before
hitting a wall, piece of equipment, etc.
Other Adverse Physical Effects
of Microgravity
• Penile fracture
– A misguided movement could cause excessive
lateral or downward buckling of the erect penis
– This results in a tear in the fibrous tissue within
the penis and an injury that decisively interrupts
any resumption of coitus
Other Adverse Physical Effects
of Microgravity
• A penile fracture produces:
• A sharp snapping, cracking, or popping sound
• Excruciating pain, swelling, bleeding, and
deformity of the penis
• Having to answer many embarrassing questions
from Mission Control
• A sharp fall in the stock price of space tourism
companies
Other Adverse Physical Effects
of Microgravity
• Treatment of a penile fracture
– Cold compresses, pressure dressings, splinting
– Analgesics
– Surgery is strongly recommended to repair a penile
fracture
– Surgery will need to be delayed for a painfully long
time, unless one of your crewmates happens to be a
urologist and has proper surgical supplies on hand
– Medical treatment alone is much more likely to result
in long-term complications, including erectile
dysfunction, permanent curvature, abscess, etc.
Potential Solutions to Physical Issues
with Performing Sex in Space
• Restraining one or both partners:
– At least one partner could be restrained by means
of footholds in a solid surface or being bound by
belts/cords to a flat surface (space bondage?)
– The other partner could be more loosely bound to
the other by belts, short cords, handles etc.
– Alternatively, both partners could be within a
loose covering/blanket/mesh that in turn is
fastened to a surface
Potential Solutions to Physical Issues with
Performing Sex in Space
• Other issues:
– A third person secured nearby can be employed as a
helper to give a well-timed push or restrain excessive
backward movement of one of the two “busy”
partners
– This technique is reportedly used by dolphins, who
must have some very interesting tales to tell
– Partners will need to be careful enough not to be
injured but not too anxious about injury that
performance suffers or a “catastrophic system failure”
occurs
Potential Solutions to Physical Issues with
Performing Sex in Space
• Fluids and other matter generated during sexual
activity need to be contained
– Potential substances include perspiration (which also
beads up on skin), saliva, hair, blood, and those originating
from the genitalia
– Free fluids of any kind form globules in microgravity that
float until they strike a surface, are inhaled, etc.
• Body heat dissipation may be less efficient, making
active, close contact literally and uncomfortably
“hot”
• Noise and unpleasant smells may be inhibiting
Overall Assessment
• If proper care and precautions are taken, sex in space
could potentially be successfully performed
• Rats (2 males and 5 females) aboard Cosmos 1129
(1979) were able to copulate in microgravity
• Mekada fish also successfully mated on STS-65
(1994) and produced viable offspring born in space
• The rats, fish, and any humans who’ve ever “done it”
in space aren’t saying whether the experience was
worth it or not
Overall Assessment
• Psychological effects are also potentially
serious
– Jealousy, love triangles, and interpersonal conflicts
can occur in isolation of space
– Incidents have occurred in comparable situations
in remote outposts (e.g. Antarctica)
– “Soap opera in space” could endanger crew and
mission
• Lisa Nowak incident
Conception and Pregnancy in Space
• There are important reasons to prevent sex in
space from producing conception and pregnancy
– This is clearly not desirable on initial missions to the
Moon or Mars due to limited medical resources
available to support the mother and the embryo/fetus
(e.g. an ectopic pregnancy)
– Microgravity, lower gravity on the Moon and Mars,
and increased radiation exposure in these
environments have potentially harmful, even deadly
effects on the developing embryo/fetus and children
Contraception in Space
• No method of birth control short of full
sterilization is 100% effective in an otherwise
fertile man or woman
• Various “temporary” contraceptive methods can
approach but not reach 100% effectiveness
• The effectiveness of chemical means of
contraception (e.g. birth control pills) in micro- or
low gravity environments is unknown
Can Conception Occur in Space?
• In microgravity, ejaculated spermatozoa can
“stay put” within the vagina and be ready for
transport to the uterus and fallopian tubes
• Transport of spermatozoa to and through
these organs is produced by muscle
contractions, ciliary action, and the intrinsic
motility of spermatozoa
• Microgravity should not significantly affect
conception
Can Conception Occur in Space?
• Microgravity and spaceflight may have
contraceptive effects
• Menstrual dysfunction is likely in woman
astronauts during prolonged stays in space
–
–
–
–
Disturbances in circadian rhythms
Intensive exercise needed for pre-flight training
Stress
Potential disturbance of the hypothalamic-pituitaryovarian axis could result in lack of ovulation or
excessive menstrual bleeding
Can Conception Occur in Space?
• Menstrual dysfunction:
– Microgravity might induce retrograde
menstruation (regurgitation of uterine blood and
tissue backwards through the fallopian tubes and
abdominal organs), producing endometriosis and
infertility
Can Conception Occur in Space?
• Effects of the space environment on male
fertility
– Fall in testosterone levels and sperm motility
could reduce fertility
– Toxins used in life-support systems, propellants,
etc. could reduce sperm counts
Can Conception Occur in Space?
• Higher radiation levels in space affect both
male and female fertility
• Sperm cells are the most radiosensitive cells in
a man’s body
• Radiation can damage or destroy sperm cells,
leading either to reduced fertility or genetic
defects in offspring if conception does occur
Can Conception Occur in Space?
• Sperm cells are produced and destroyed over
an approximately 74-day cycle
– Sperm counts and quality will eventually return to
normal after only low-dose radiation exposure
– Higher-dose radiation exposure could produce
prolonged infertility
– Radiation doses needed to destroy all sperm cells
are usually lethal
Can Conception Occur in Space?
• Effects of radiation exposure on fertility in
women
– The ovaries are 5 to 7 cm below the skin, which
attenuates the radiation exposure they receive
compared to a man’s testes
– Oocytes (immature egg cells) in the ovaries are
more radioresistant to genetic defects than sperm
cells
– However, oocytes are not replaced if damaged,
while new sperm cells are produced
Can Conception Occur in Space?
• Effects of radiation exposure on fertility in
women
– A single acute dose of 300-400 rems usually
results in destruction of all oocytes and ends
further estrogen production by the ovaries
– Smaller, repeated doses of radiation have
cumulative effects
– Radiation exposure can also cause endometriosis
Conception in Space
• Ovulation and fertilization occurred in female rats
aboard Cosmos 1129
• However, all embryos were absorbed and never
carried to term
• Male rats onboard Cosmos 1129 successfully
mated with earthbound females after their flight
– Offspring had a higher rate of developmental
abnormalities, including growth retardation
Conception in Space
• Mekada fish did produce viable offspring after
mating on STS-65 (1994)
• The overall effects of the space environment
on human fertility and conception are
unknown
Pregnancy in Space
• This could be due to a pregnancy originating
in space or a preexisting one at the time of
entry into space
• Adverse effects of microgravity and especially
radiation would be expected to be greatest
during the earlier stages of pregnancy
– Increased risk of genetic damage to the embryo
– Adverse effects on the mother
Pregnancy in Space
• Other adverse effects during early pregnancy
– Symptoms of “morning sickness” such as nausea
and vomiting would be more difficult to manage in
the space environment, especially if combined
with similar symptoms of Space Adaptation
Syndrome
– Possibility of “hyperemesis gravidarum” with
severe vomiting, dehydration, and liver damage
Pregnancy in Space
• The full range of complications that can threaten the
life and health of both mother and fetus could also
occur in space
• Limited medical care in space, particularly at long
distances from Earth (e.g. on the Moon or Mars),
could lead to serious injury or death to mother and
fetus
– Common complications that usually are not lifethreatening, such as UTIs and gestational diabetes, will be
more difficult to treat due to limited medical supplies
Pregnancy in Space
• Preeclampsia can occur in the second and
third trimester
– Hypertension
– Proteinuria
– Headache
– Visual disturbances
– Can worsen into eclampsia, with potentially fatal
seizures and coma
Pregnancy in Space
• Hemorrhagic complications
– Abruptio placentae (partial separation of the placenta
from the uterine wall)
– Limited blood supplies in space and the hypovolemia
and mild anemia that occur in microgravity could
worsen the effects of blood loss on mother and fetus
– Fetus would be more sensitive to the mother’s blood
loss from any cause, potentially causing problems
from low birth weight to anoxic encephalopathy to
death
Pregnancy in Space
• Other potential complications:
– Ectopic pregnancy
– Pre-term labor
– Risk of rupture of the amniotic sac during
acceleration or deceleration (e.g. launch and reentry)
– Toxins within spacecraft (e.g. nitrogen tetroxide or
hydrazine) could cause respiratory distress or
anoxia to mother and fetus
Pregnancy in Space
• Beneficial effects of microgravity
– Reduction of incidence of varicose veins and
edema (swelling) of the legs
– Reduced problems with back pain and difficulty
moving associated with terrestrial pregnancy
– Lightheadedness caused by gravity-dependent
compression of the IVC by an enlarged uterus in
the supine position will not occur
Pregnancy in Space
• Birth in microgravity or low gravity
– Woman and assistants need to be secured
– Maintaining sterility and containing fluids (e.g.
amniotic fluid) will be challenging
– Anesthesia (local or intravenous) could be used
• Spinal/epidural anesthesia is partly dependent on
gravity for its effectiveness
– Cesarean section would require higher level of
sterility, trained personnel, and proper equipment
Pregnancy in Space
• Other risks to the embryo/fetus
– Decompression sickness caused by sudden cabin
decompression can injure the mother and
especially the fetus
– Effects on the mother include difficulty breathing,
pain in the limbs, weakness, paralysis, and
seizures
– Caused by release of nitrogen dissolved in blood
and other body fluids as bubbles
Pregnancy in Space
• Other risks to the embryo/fetus
– In the fetus, nitrogen bubbles can form directly in
arterial blood and can also pass from veins into
the arterial system through the foramen ovale and
ductus arteriosus
– These bubbles can impair blood supply to critical
organs, including the brain
Pregnancy in Space
• Other risks to the embryo/fetus
– Radiation risk to embryo/fetus in space is high
– Suggested maximum cumulative radiation exposure to
the embryo/fetus during all nine months of pregnancy
in terrestrial female radiation workers is 0.5 rem
(normal annual background exposure per year is 0.1
to 0.2 rem)
– In LEO, annual radiation exposure is 14 to 21 rem
– Radiation exposure could be much higher in deep
space or during a solar particle event
Pregnancy in Space
• Radiation risks to the embryo/fetus
– High acute radiation exposure during the first two
weeks following conception are most likely to
result in destruction of the zygote (first four days
after conception) or embryo (remaining 8 weeks
following conception)
– Developmental abnormalities are most likely to
occur with radiation exposure between 8 to 25
weeks after conception
Pregnancy in Space
• Radiation risks to the embryo/fetus
–
–
–
–
–
–
–
–
Cataracts
Abnormal genitalia
Microcephaly
Microphthalmia
Decreased life span
Mental retardation
Possible increased risk of childhood leukemia
Dose-dependent reduction in IQ
Overall Risks of Conception and
Pregnancy in Space
• The probability of conception occurring, if the
most effective level of contraception is used, is
low
• However, the risks to the mother and especially
the developing embryo/fetus are high if
conception does occur
• These risks are magnified the longer the mother
and her embryo/fetus are in space and the
farther away they are from needed medical care
on Earth
Overall Risks of Conception and
Pregnancy in Space
• NASA’s current Medical Standards specifically
disqualify any pregnant woman from going
into space due to these risks
• None of the problems with conception and
pregnancy are insurmountable
– Systems using artificial gravity
– Improved protection against radiation
– Adequate medical infrastructure
Overall Risks of Conception and
Pregnancy in Space
• In the current state of space exploration, the
risk-benefit ratio of conception and
particularly pregnancy in space is very
unfavorable
Kids in Space
• Potential risks of microgravity or low-gravity
and radiation exposure are significantly
greater in children than in adults
• Unlike adults, the bones and muscles of
children are still developing
• Long-term exposure to microgravity is likely to
result in growth retardation, particularly in the
long bones of the thighs and legs
Kids in Space
• Other potential adverse skeletal effects:
– Delayed closure of the fontanels of a baby’s skull
– Short stature due to reduced lengthening of long
long bones and premature closure of epiphyseal
(growth) plates
– Abnormal development of vertebrae, potentially
resulting in nerve compression syndromes
Kids in Space
• Other potential adverse skeletal effects:
– Adult astronauts need to perform vigorous
exercise to maintain bone and muscle mass of
about 85% of preflight levels
– Infants, babies, and small children would not be
able to cooperate in such intensive exercise
programs
– This could result in levels of bone and muscle
mass well below 85% of normal
Kids in Space
• Other adverse effects
– Infants and babies raised in microgravity wouldn’t
learn how to walk or develop “normal”
neurovestibular reflexes (e.g. those associated
with balance)
– How prolonged exposure to low or microgravity
would affect overall neurological (especially brain)
development is unknown
Kids in Space
• Other adverse effects
– Long-term radiation exposure in the space
environment will increase lifetime risk of cancer
– Immature immune system may increase risk of
infection
– The presence of small children in a spacecraft, with all
its potential dangers, is a recipe for disaster
• For example, “Daddy, what does this button do?”
immediately followed by the whole family breathing
vacuum
The Current Status of Sex in Space
• There is a marked dichotomy between some
perceptions (including those in SF) about what
sex in space is like and what it really is at present
• Based on current technology, sex and its
consequences in space are both risky and
potentially deadly
• However, all of these risks can and must be
significantly reduced with further advances in
technology and medical infrastructure for the
successful colonization of space
Sex with Aliens?
• It requires at bare minimum some type of
“complementary” anatomy
• It also requires faith that alien sexual practices do
not lead to unexpected consequences
•
Hopefully the relevant part of the alien’s anatomy does not
have teeth, nor does it have sharp spikes that suddenly
extrude out of it during a critical moment of intimacy
• There may be an embarrassing discovery that the alien is
not really the gender you thought, particularly if its
species has more than two genders
• Mating with alien females whose post-coital habits are
similar to a terrestrial black widow spider or praying
mantis may lead to abrupt termination of afterglow
Offspring with Aliens?
• Very unlikely that interspecies parenthood is possible,
even with the most advanced genetic engineering
• Alien physiology will almost certainly be radically
different from the terrestrial variety
• They evolved under different average atmospheric pressure
and content, gravity, radiation levels, etc. than humans
• They have different DNA (if any), proteins, amino acids,
cells, etc. than life as we know it
• We would have more in common genetically with a
rutabaga than we would with an alien, and humanrutabaga hybrids (rutamans?) appear to be uncommon
The way Hollywood sees it…
“Sorry if I seem a little too touchy-feely. We Metalunan
mutants don’t get out much.”