https://www.youtube.com/watch?v=ii6QZzTL62M

Have YOU had sex in zero gravity? Has anyone? Bestselling author and scientific investigatrice extraordinare Mary Roach…investigates!

The following passages are excerpted from Mary Roach’s new bestseller PACKING FOR MARS: THE CURIOUS SCIENCE OF LIFE IN THE VOID, published by W. W. Norton & Company this month.

Excerpt from Chapter 12: THE THREE DOLPHIN CLUB

What fascinates most people about sex in space is not the altitude of the participants but the fact that they’re weightless. That being the case, a parabolic flight might do the trick…

Ed. note: a parabolic flight is when a plane (like a Boeing 727) flies in a series of arcs that simulates weightlessness for the passengers on the plane. You can book your own flight HERE!

Only pornographers are suitably motivated to take on the expense of chartering an entire plane for the prospect of weightless sex. Playboy has contacted the Zero G Corporation, as did a producer at Girls Gone Wild. “You wouldn’t believe how hard they tried and how much they offered,” said my contact of Girls Gone Wild. The producer and crew ended up chartering a plane in Russia, though no one had sex. It’s just more shots of girls displaying their unfettered bosoms, this time additionally unfettered by gravity.

Some months later, leafing through a European magazine called Colors, I saw a reference to a 1990 porn film called The Uranus Experiment, whose producer had apparently chartered a jet for a parabolic flight. “As the plane dived to earth, there was just enough time to film their copulation scene.” The star of the film was a Czech actress named Silvia Saint. Could Ms. Saint be the first human being to have had weightless intercourse?

Though Silvia Saint has a healthy presence on the Internet, her email address proved elusive. An acquaintance who writes a popular online sex column suggested reaching out to a well-connected “adult PR person” she knows named Brian Gross. (Because I am not an adult, I took delight not only in the name but in the job description, imagining an alternate category of “child PR person” and wishing that some of them worked at NASA.) A glance at Mr. Gross’s client endorsements marked him as a man of great versatility, having represented, at one time or another, both ABC News and Booble: The Adult Search Engine. Mr. Gross provided a lead, which led to another, who said that Saint had left the industry five years ago, “moved back to the Czech Republic, and dropped off the face of the earth.”

Next stop, Berth Milton, the man whose Barcelona company, the Private Media Group, produced The Uranus Experiment. Milton, an affable family man with an unplaceable accent, arranged to have downloads of the Uranus films (it’s a trilogy!) sent to me and promised to help track down Ms. Saint. The plane upon which the historic act had transpired, he said, was part of a fleet of corporate jets, of which Mr. Milton owned a timeshare.

“You asked a corporate jet pilot to fly parabolas?” I said.

“Exactly.”

“Had the pilot ever done this before?”

“No.” This was surprising information. But Milton went on about the wear and tear on the jet engines, and how the plane was grounded for two days afterward for inspection and maintenance, and so I chose to believe him.

Milton hadn’t been there, so he couldn’t remember details from the zero-gravity scenes. This was ten years ago, after all, and Private Media was then releasing ten movies a month. He did recall the cameraman, who was notable among his kind for having been, at one time, a cameraman for Ingmar Bergman.

Milton added that he didn’t care for Bergman. “He won a lot of awards, but nobody was looking at his movies. He’s just depressing. There’s no joy.”

I mentioned Fanny and Alexander.

“Okay, that’s probably the only one that you could watch the whole movie. The rest are terrible.”

I have to admit that I felt more joy while watching The Uranus Experiment 1 than I did watching The Seventh Seal. The film opens with a cosmonaut sitting naked on an examining table at the Russian space agency. A white adhesive EKG electrode is stuck to his chest like nicotine patch. It is an odd touch, given that he’s there to deliver a semen sample. In the next room, jowly Russian space agency men discuss a top-secret experiment “to find out how zero G affects the sperm production.” Cut to a blonde in a snug white lab coat, a test tube dangling from her manicured fingertips. “Hello,” she says, “What a beautiful organ you have there.”

I fast-forwarded through this scene and the one at NASA (here pronounced Nassau) headquarters, wherein we learn how the agency chooses its female interns. (An aerospace degree appears unnecessary.) I stopped fast-forwarding at the point where the action moves to zero gravity. Two orbiting space shuttles, one Russian and one American, have commenced a belly-to-belly docking maneuver. Even the spacecraft are having sex.

The hatch between the two craft is barely opened and the two crews have their flight suits off. Silvia Saint is holding vertical, bobbing up and down as though taking a dip in a mild chop. Hang on. Hold the phone. Her ponytail is hanging down her back and other things are hanging down her front. Without gravity, there should be no hangy-downy. This wasn’t shot in zero G! The actors’ lower legs are hidden behind a console; they’re just rishing up and down on their toes and waving their arms in the air.

A press release for the trilogy, I note, makes reference to just a single shot “in total weightlessness,” and it’s in The Uranus Experiment 3. I get up off the couch to eject No. 2, but I can’t just now. An astronaut orgy, led by a Commander Wilson, has gone live on the giant wall screen at Mission Control. It’s being broadcast around the world. Scandal and chaos! NASA is shut down. The American president is on the phone. His suit is too big for him and he’s working from a cheap motel room. “This is the work of the KGB! I can smell it.”

Commander Wilson and Silvia Saint continue to flaunt the NASA Crew Code of Conduct in installment 3. Perhaps it’s my imagination, but Commander Wilson appears better endowed than he did in 1 and 2. Could this be the effects of weightlessness? Without gravity pulling the blood down into the lower half of the body, more of it remains in the upper half. Breasts are larger, and anecdotal information suggests penises enjoy the same plumping effect. “I had an erection so intense it was painful,” writes astronaut Mike Mullane in Riding Rockets. “I could have drilled through kryptonite.”

“I have heard others say exactly the opposite,” astronaut Roger Crouch told me, craftily leaving his own drill bit out of it. I called up on NASA physiologist John Charles to referee. Charles said that according to Buzz Aldrin, the Mercury and Ginimi astronauts reported a definite lack of activity in that region. “They were going to give an award to the first man who demonstrated a response. Though how to prove it?” Charles mused. He sided with Aldrin and Crouch. And John Charles has medical science on his side. The dividing line between the part of the body that gets more fluid in zero gravity and the part that gets less is right around the diaphragm. It’s called the hydrostatic indifference point. “The male jumblies are below that point,” says Charles, “and so would seem to be drained, not engorged.”

This could have posed a challenge for The Uranus Experiment’s male cast. But it didn’t, because guess what. Nothing was shot in zero gravity. The cameraman simply filmed the ejaculating commander on his back and then flipped the image upside down so he appears to be floating. I happen to know what a “cum shot in total weightlessness” would look like. I know because I’ve read the 1972 NASA study “Some Flow Properties of Foods in Null Gravity,” and those foods include butterscotch pudding and potato soup. The paper includes the dietician’s rendition of the zro-gravity cum shot: a demonstration of how a stream of milk “rapidly forms a perfect sphere.” Commander Wilson’s butterscotch pudding does not do this.

A fond but accusatory email to Berth Milton earned no reply.

MARY ROACH is the author of “Stiff: The Curious Lives of Human Cadavers,” “Spook: Science Tackles the Afterlife,” “Bonk: The Curious Coupling of Science and Sex,” and “Packing for Mars: The Curious Science of Life in the Void.” She lives in Oakland, California.