Has anyone made love in space?

Both the Russian space station, Mir, and the American space shuttle have had crews of mixed genders aboard. Some of the shuttle missions have gone longer than a week. Many of the Mir crews have been in orbit for months at a time.

Has nature taken its course, up there in orbital space?

Neither the Russian nor the American space agencies will admit that there have been sexual encounters aboard their spacecraft. The chances are there haven't been--- yet. The Mir space station is small, cramped, and cluttered with equipment. The space shuttle's living area is crowded. Neither Mir nor the shuttle offers much in the way of privacy.

However, the International Space Station, now being built by NASA with contributions from Russia, Japan, and the European Space Agency, will be roomy enough. Crew members will have individual privacy spaces, zero-gee bedrooms. Mixed crews will be aboard the ISS for weeks and months at a time. There will even be married couples in some of the crews.

The inevitable will happen soon, even if it hasn't already.

Imagine making love in zero gravity. You and your lover are weightless, drifting languidly in midair as if in a dream, no longer pinned down to a mattress or a couch, free to use both arms and both legs. Everything floats buoyantly in zero gee because there is no gravity to make things sag.

Well, not quite . . .

The Physiological Facts

Interesting things happen to the human body in zero gee.

You grow taller by a couple of inches. Your waist and legs become hinner. Your face takes on a higher-cheeked, slightly oriental cast. You tend to lose a few pounds of body liquids, at least for the first few days.

All this happens to your body because it is suddenly weightless, free of the constant force of gravity that has been trying to pull you down to the center of the Earth all your life.

You grow taller because your spine unbends. Earth's gravity working on your spine compresses the discs between your spinal vertebrae, squeezing the vertebrae closer to one another, forcing your body into an s-shaped curvature. In zero gee, your weightless vertebrae are no longer being squeezed. The discs expand and you grow taller by two inches or so.

However, in zero gee there is a difference between the head-to-toe length of your body and your "effective body height." In weightlessness, your body tends to take on a simian-like crouch when relaxed, with the back slightly bent and the arms floating up to chest height. It is rather like floating in warm, buoyant water. Space medics call this the "neutral body posture." You can stand straighter if you want to, but it takes some exertion to do so.

The fluids inside your body feel the effects of zero gravity, too. Instead of being pulled down they suddenly are weightless. Astronauts have measured three-inch decreases in their waist sizes, because their internal fluids tend to shift upward, into the chest.

Your legs will also slim down in zero gee, in part because the blood and other fluids that tend to pool in your lower extremities on Earth now migrate to other parts of the body. Increased height, wasp waist, fuller chest, slimmer legs . . . it all sounds pretty good. But there's a down side to your body's reaction to being in orbit.

Without having to fight against the constant stress of gravity, the body's muscles tend to lose strength and mass. The medics call this "deconditioning," which is slightly misleading. Your body is adapting to the conditions in which it finds itself. It is only "deconditioned" when you have to return to Earth and suddenly find yourself facing a full terrestrial gravity again.

Still, the progressive loss of muscle tissue and strength is a problem that must be dealt with. The heart is a muscle, remember, and when it is pumping blood that is weightless, it becomes just as deconditioned as any other muscle of your body.

Moreover, your bones slow their production of calcium after several months in weightlessness. Again, the body is merely adapting to the conditions of zero gee. But calcium-poor bones can become brittle and too weak to support your weight when you return to Earth.

The answer to the problems of deconditioning lies in exercise. Stressing the heart and other muscles, as well as the bones, is a necessity for anyone who spends more than a few days in orbit.

Astronauts and cosmonauts have used gym equipment and stationary bikes to exercise their muscles, including their hearts. Perhaps one day sexual activities will be a prescribed (and preferred) part of an astronaut's exercise routine.

Space Sickness

There is also the problem of space sickness. Most people get nauseated when they first go into orbit.

NASA calls it "space adaptation syndrome," or SAS, and for once the technical jargon tells it like it is.

Space sickness is not like sea sickness or any other kind of motion sickness. It is truly a problem of your body's adaptation to the weightless conditions of orbit as your bodily fluids shift around inside you.

Astronaut William R. Pogue, who spent 84 days in orbit aboard the Skylab space station in 1973-74, describes his feeling in his delightful book, How Do You Go to the Bathroom in Space? this way:

"The first thing you notice when you go into space is an absence of pressure on your body. You may feel lightheaded or giddy. After a half hour or so, your face may feel flushed and you might feel a throbbing in your neck. As you move about, you will notice a strong sensation of spinning or tumbling every time you turn or nod your head. This makes some people uncomfortable or nauseated. You will also have a very 'full feeling' or stuffiness in your head. You may get a bad headache after a few hours, and this too may make you feel sick to your stomach."

Most astronauts adjust to weightlessness within a day of entering orbit. Experience seems to help, and NASA medical researchers have developed medicines and training routines that alleviate SAS. Psychologists have determined that it helps to have the spacecraft interiors designed with a visually obvious "ceiling" and "floor." In zero-gee, "up" and "down" lose their physical meaning. Everything that is not fastened down tends to float.

There is no need for chairs in zero-gee. Nor for beds. Sleeping accommodations aboard the ISS will consist of cocoon-like zippered mesh bags fastened to a privacy compartment's wall. Once zippered up, the mesh will keep its occupant from floating loose while asleep.

Even the best-trained, most experienced astronauts need at least a few hours to get accustomed to zero-gee. Once you do become adjusted to weightlessness, however, you will probably experience an almost euphoric feeling. You can float through the air inside your space vehicle, doing weightless acrobatics almost effortlessly. In orbit, astronauts can lift masses that would be impossibly heavy on Earth. During a Skylab mission, astronaut Alan Bean demonstrated the effect of zero gee by doing pushups with teammates Jack Lousma and Owen Garriott on his back. However, although everything is essentially weightless in orbit, objects still have mass and therefore inertia. A massive object in motion can still injure the unaware person who thinks it can be stopped with a fingertip.

Newton and Lovemaking

In weightlessness, Isaac Newton's laws of inertia become strikingly obvious: a body in motion will remain in straight-line motion unless and until some outside force deflects or stops it. You can launch yourself across the interior of a space station's living module and sail smack into the opposite wall, if you are not careful.

This has fascinating implications for foreplay. Imagine two human bodies floating in zero-gee. The slightest touch on your partner will send him or her bobbing away from you, in three dimensions: up and down, as well as north, south, east and west. You are going to need a compartment with padded walls, or you will have to confine your lovemaking to an intimately small cubicle, where there is no room to roam.

Since the heart can pump blood more effectively in zero-gee, erections will most likely be easier to accomplish and maintain.

But now comes the crucial moment. How can coitus be achieved when the slightest touch can send a body bouncing away from you?

NASA has already solved this problem---for machines. When two spacecraft are "mated" in the weightlessness of orbit, they inevitably are fitted out with "male" and "female" appendages that fit together. In NASA parlance, the approach and connection of two spacecraft is called "rendezvous" and "docking." Some rendezvous and docking procedures are done by remote control, directed by technicians on the ground; others are accomplished by astronauts or cosmonauts aboard the spacecraft.

If two orbiting spacecraft can be mated by remote control, a human couple with grasping hands and willing minds should be able to solve the problems of rendezvous and docking gladly. Solving this problem should, in fact, be quite enjoyable.

Babies and Honeymoons

Despite the problems presented by SAS and Newtonian inertia, human couples will meet and mate in zero-gee—if they have not done so already. The rendezvous and docking problems are trivial, compared to the power of the sex drive.

There seems to be no physiological reason why a woman could not get pregnant in zero-gee. Sperm cells are guided to the egg cell by chemical signals that the ovum emits; in the microscopic cellular world, pervaded by liquid, the human-scale concepts of "up" and "down" do not apply even on Earth.

How a fetus will develop in the space environment is another, and largely unknown, story. Weightlessness itself might not be a problem, although the increased radiation aboard a spacecraft might pose difficulties if the mother remains in space during the entire term of her pregnancy.

I have a vision of a time, not so far in the future, when we will see zero-gravity honeymoon hotels in orbital space. Even if the newlyweds suffer from SAS for a day or so, the remainder of their stay in weightlessness could be truly "out of this world" pleasure for them.

I even have an advertising slogan that an orbital honeymoon hotel could use: "If you like waterbeds, you're going to love zero gee."

Dr. Ben Bova is the author of more than 100 futuristic novels and non-fiction books. His latest novel is Venus, an adventure set on Earth's "sister planet."