In outer space, can you hear feminists scream? Man first went into space in 1961, the first woman in 1963. But even now, of more than 450 astronauts who have flown in space, just 46 have been women. Kohled and coiffed, the American “astronettes” may look like cover girls in their staff photos, but earning the famed gold pin requires high-level qualifications and intelligence. Nasa has the same academic, physical and professional requirements for men and women, and they undergo the same training. But when it comes to getting a place in space, women haven’t always been equal to men.

US military researchers noticed that women were potentially more suited to space travel even before the Russians sent their first man, Yuri Gagarin, into space. They are smaller, lighter, eat less, use less oxygen and produce less waste. They are also less negatively affected by periods of isolation. So why have so few made it into space?

In the early days, scientists were nervous about mixed crews, in case sexual tensions detracted from the job. There was the problem of anatomy – how would they use the toilet? A specially shaped pressure suit would have to be designed. And what about menstruation?

Valentina Tereshkova became the first woman in space in 1963. The mission was a giant leap for womankind, but the Soviets had a political agenda. At the time of her selection in 1962, 13 American women pilots were making headlines as they trained for Nasa’s Project Mercury. The First Lady Astronaut Trainees, all skilled pilots, took the same tests as Nasa’s male astronauts. But they never made it to space. The final stage of testing was cancelled – Nasa sent the women a telegram stating it did “not have requirement for such a program”. The Americans wanted a man on the moon fast, and Nasa seemed reluctant to use valuable resources training women for flight. Jerrie Cobb, the first of the 13 to pass the training tests, said: “Chimpanzees are getting better treatment in the space program than women.”

Russia, still flushed with Gagarin’s success, knew that sending the first woman into orbit would be a huge coup. Nikolai Kamanin, the director of cosmonaut training, wrote in his diary: “We cannot allow that the first woman in space will be an American. This would be an insult to the patriotic feelings of Soviet women.”

They discovered Tereshkova, 25, at a parachuting club. As well as having aviation experience, and being young, brave, physically fit and strong, Kamanin found her feminine and charming. She would present a fine and plausible face for Russia’s first female voyage.

She trained for almost a year leading up to her mission but was never integrated into male cosmonaut training – women space flights were for propaganda, not scientific purposes. Still, she practised weightless flights, isolation tests, studied rocket theory and spacecraft engineering and piloted fighter planes. On June 16, 1963, she was launched into space and orbited Earth 48 times in three days. It was longer than all the US flight times combined – another triumph in the space race. She was given the flight call “Chaika”, meaning seagull. In orbit she said: “I am Chaika. I see the horizon. There is a blue stripe. This is the Earth. How beautiful it is! Everything is going well. Hello, Universe.”

Officially, the mission was a success: she had maintained her flight log, completed experiments, and taken pictures of Earth’s atmosphere, which were later used to identify its structure.

Tereshkova returned to Earth a celebrity and a national treasure. But the mission was shadowed by claims that it hadn’t been as successful as Russia stated. Vasily Mishin, the Soviet rocket pioneer, claimed Tereshkova was “at the edge of psychological stability” during the flight. And she reportedly angered physicians by handing out her uneaten meal packets as souvenirs on her return, so they were unable to analyse her food intake. She certainly suffered from space sickness during the flight – nausea and dizziness induced by weightlessness – which meant she wasn’t allowed to manually operate the spaceship, but this condition is experienced by about half of all space travellers and not peculiar to women.

Perhaps the mere suggestion that she was unable to cope put a black mark against future women astronauts, or maybe now the point was made – a woman could go to space and safely return – there was no immediate need for female astronauts. In any case, it was 20 years before the next woman journeyed into space.

Nasa began officially recruiting women in 1978. The liberated 1960s and the 1964 Civil Rights Act had helped lever women into traditionally male professions. In the press, the six women chosen for the 1978 astronaut intake were dubbed “Astronettes”, “the six beauties” and “Girls who aim for the Stars”. At the same time, British Page Three girls posed in unzipped spacesuits holding futuristic weapons.

The chosen six may have captured public imagination, but they weren’t astronauts yet.

On June 18, 1983, a young physicist and nationally-ranked tennis player, Sally Ride, changed this. She spent six days aboard the space shuttle Challenger with four male astronauts, and became the first American woman, and the second woman ever, to venture into space. But she was scathing about the attention it brought her: “I didn’t come into the space programme to be the first [American] woman in space. I came in to get a chance to fly as soon as I could.” She became a national and feminist heroine. In 1985, Ride was assigned to Nasa headquarters in Washington, DC, and led the department for strategic planning. She was later assigned to the Rogers Commission, set up to investigate the causes of the 1986 Challenger disaster, which killed seven astronauts, two of them women. One was Christa McAuliffe, 37, the first teacher in space. The other was Judy Resnik, 36, Ride’s former colleague from the class of ’78. It is said that Resnik received hate mail from feminists after her first voyage on Discovery – she was photographed in a cheerleader-style pose with the rest of her male crew.

Since those first historic flights, women have crewed, piloted and commanded space flights with increasing parity with men. There has been Helen Sharman, the first Briton in space; Eileen Collins, the first woman to pilot a shuttle; Shannon Lucid, who spent six months aboard Mir; Mae Jemison, the first African-American woman in space.

There are currently 91 astronauts in the Nasa programme; 19 are women. Dr Kevin Fong, of the Centre for Aviation, Space and Extreme Environment Medicine, believes we have entered a second space age – one where women are equal to men. “It’s depressing that it took so long, but now there’s a representative mix,” he says. “It’s not about ‘top gunnage’ any more… It’s about mature, scientific operations in space… Inclusion of women has come with that maturity.