In 2013, NASA announced its team of eight new astronaut recruits, and for the first time ever, there were just as many women as men — four of each.

This isn’t the first time NASA has had the opportunity to send a group of women into space. Back in the 1960s, when the space program was gearing up, 13 female pilots had passed all the same tests — both physical and psychological — that the male Mercury 7 astronauts had to pass. The Air Force flyers were expecting to make the next step to a Navy facility in Florida for more tests, and to hopefully land a spot on the astronaut training program from there. But before any of that could happen, the 13 women got telegrams from NASA informing them that they wouldn’t be leaving Earth.

Even though the women went to Washington, D.C., to plead their case, they were turned down. Top brass from NASA and other astronauts decided it was culturally problematic. As recounted in the 2003 book, "The Mercury 13," by Martha Ackmann, influential astronaut John Glenn said, "The men go off and fight the wars and fly the airplanes and come back and help design and build and test them," Glenn testified before the Subcommittee of the House Committee on Science and Astronautics. "The fact that women are not in this field is a fact of our social order. It may be undesirable." (Frankly, I'm not sure what that actually means — do you?)

Astronaut Scott Carpenter also testified against women going into space, though he later said he regretted doing so.

Twenty years passed before any American woman got a chance to go to space — in 1983, Sally Ride broke that barrier. (Though a Russian woman, Valentina Tereshkova, did go up in 1963, making her the first woman in space.) In 1999, the first woman to command a space mission was Eileen Collins.

Of those original 13 women, flight instructor Wally Funk (who was told, when she was tested, that she did better than the men — and better than John Glenn on some tests) still has dreams of space flight — she'll be going up in Virgin's program when it lifts off. She told Time of her disappointment in being discriminated against: "It was the era when women were in the kitchen. Space travel was the old-boy network."

But what if women aren't just as good as men for space travel — but better?

Kate Greene recounted her experience as a test subject for NASA’s HI-SEAS (Hawaii Space Exploration Analog and Simulation) program for Slate. She argues that women would be less expensive and maybe better suited to interstellar travel. The crux of her argument is that women need a lot less food, and take up less space. She detailed the following of her test run atop Hawaii's Moana Kea: “Week in and week out, the three female crew members expended less than half the calories of the three male crew members. Less than half! We were all exercising roughly the same amount — at least 45 minutes a day for five consecutive days a week — but our metabolic furnaces were calibrated in radically different ways. During one week, the most metabolically active male burned an average of 3,450 calories per day, while the least metabolically active female expended 1,475 calories per day. It was rare for a woman on crew to burn 2,000 calories in a day and common for male crew members to exceed 3,000.”

This mock Mars mission gives NASA data on real people in the circumstances they might find when they head to Mars.

Greene doesn't just make her argument from the data she recorded during her mock mission; she looked into NASA contractor Alan Drysdale's report on physiological metrics, where he compared a small woman to a large man in terms of energy needs. "Drysdale found that a fifth-percentile woman would use less than half the resources of a 95th-percentile man. While we didn’t have a woman on the HI-SEAS crew who was in the fifth percentile, our stats were similar to the predictions," she writes.

When she spoke to Drysdale, he said that an all small-woman crew could launch for half the payload cost of an all-male one. "Small women haven’t been demonstrated to be appreciably dumber than big women or big men, so there’s no reason to choose larger people for a flight crew when it’s brain power you want," Drysdale told Greene. "The logical thing to do is to fly small women."

If women do as well on physical and psychological tests for space flight (and there is at least some evidence they would do better with the psychological stresses of working in a small space with a limited crew), and if they use fewer resources, saving money and fuel, then it's surprising we haven't seen more female astronauts, especially since they've been willing and interested for more than 50 years.

Well, not surprising when you consider cultural assumptions and stereotypes and limitations long placed on women, which has been the only thing holding them back, and especially when it comes to space exploration.

Starre Vartan ( @ecochickie ) covers conscious consumption, health and science as she travels the world exploring new cultures and ideas.