Why can't a woman astronaut be more like a man? Because NASA/TREK won't let her, laments Marina Benjamin, and that's the trouble with ...; the space girls

NASA/TREK: popular science and sex in America by Constance Penley, Verso, pounds 11

I suspect that the Pathfinder mission to Mars has sent X philes everywhere into a tail-spin. The problem is this: how do you sustain belief in a conspiracy theory which casts Nasa chiefs as sinister machinators bent on covering up their knowledge of the truth out there, when they have been exposed for all the world to see as geeks who delight in nothing more than an ability to drive robo-toys by remote control? Granted, the scientific imagination needs only the barest of factual foundations on which to build its fantasies; the science-fiction imagination even less. But the most determined X phile will have trouble imputing dark purposes to a buggy that spends hours examining a rock and would lose a race with a snail.

That Nasa has scored a point against The X Files in the space fantasy league will not be lost on the agency. Aware of its own metaphoric potential, and of the ease with which that potential may be manipulated, it has for years sought to align itself with the Utopian quests and avowed internationalism of Star Trek. From dubbing its Mission control computers Scotty and Uhura and naming the first shuttle Enterprise to scattering Star Trek creator Gene Rodenberry's ashes in space, Nasa has consistently modelled itself on the Space Federation.

In the late Seventies, it even recruited actress Nichel Nichols (Lieutenant Uhura) to help encourage women and ethnic minorities into its astronaut corps. The ploy worked: Mae Jamison, who in 1992 became the first African- American woman in space, cited Uhura as her inspiration. From such evidence, Constance Penley convincingly argues for the existence of a single symbolic entity: "Nasa/Trek". She contends that "Star Trek is the theory, Nasa the practice". It's a bold thesis. Alas, Penley takes it in only one direction: Nasa/Trek's ambivalence towards the role of women in space.

Never mind the degrees in physics and medicine, the flying hours notched up piloting jet aircraft or the years of intensive training: above all else, Nasa needs women in space to be good mothers, competent teachers and nurturers of men. On the ground, they must play down their extraordinariness, writing books for children, and talking to journalists about their emotional investments in inner space rather than their scientific experiments in outer space.

Crucially, had Nasa not been so insistent on the absolute ordinariness of Christa McAuliffe - the teacher in space blown to smithereens in the Challenger disaster in 1986 - it might have salvaged its public reputation. As it was, McAuliffe's apple-pie make-over left the entire American nation thinking, "it could have been me".

In the midst of exploring various fictional subversions of the standard narrative of women in space, Penley stumbles into a space as strange in its own way as the interstellar void: the underground world of "slash" fiction. This pornographic literature, written on home computers and distributed by mail order, makes explicit the homoerotic relationship between Kirk and Spock that many believe was the hidden subtext of the original Star Trek series. Its aims are Utopian. In between bouts of sex, the plots involve the space crusaders on a mission to save the world.

But they are Utopian in their sexual dimension as well, expressing equality through homosexuality and interracial harmony in the love between man and Vulcan. The real warp-factor, however, is that slash fiction is produced not by gay men but by straight women Trekkies who would like to have seen Lt Uhura give Captain Kirk a run for his money.