US and Russian astronauts have had sex in space for separate
research programmes on how human beings might survive
years in orbit, according to a book published yesterday.

Pierre Kohler, a respected French scientific writer, says in The
Final Mission: Mir, The Human Adventure that the subject is
taboo both at Nasa and at mission control in Moscow, but that
cosmic couplings have taken place.

"The issue of sex in space is a serious one," he says. "The
experiments carried out so far relate to missions planned for
married couples on the future International Space Station, the
successor to Mir. Scientists need to know how far sexual
relations are possible without gravity."

He cites a confidential Nasa report on a space shuttle mission in
1996. A project codenamed STS-XX was to explore sexual
positions possible in a weightless atmosphere.

Twenty positions were tested by computer simulation to obtain
the best 10, he says. "Two guinea pigs then tested them in real
zero-gravity conditions. The results were videotaped but are
considered so sensitive that even Nasa was only given a
censored version."

Only four positions were found possible without "mechanical
assistance". The other six needed a special elastic belt and
inflatable tunnel, like an open-ended sleeping bag.

Mr Kohler says: "One of the principal findings was that the
classic so-called missionary position, which is so easy on earth
when gravity pushes one downwards, is simply not possible."

John Henley, Guardian Unlimited, 3 December 2007