It's an interesting experience watching older, perhaps somewhat dated science fiction movies, as well as reading old stories. As long as you can remind yourself that the people behind those films lacked the information available to us now, it is still possible to enjoy old stories of space exploration.
Of course from a technological standpoint, the claims of some can be jarring. We're still waiting on those interstellar-travelling flying saucers Forbidden Planet promised we'd have by 2002 and any story claiming Venus is capable of supporting intelligent life seems outright insane now that we know that planet is a blazing inferno with an unbreathable atmosphere and temperatures supposedly hot enough to melt lead. You just have to remember that the filmmakers did not have access to the same information we have now. Conquest of Space had some notable errors in its vision of the Martian surface, but back then they didn't have any of the photographs of Mars that we do now and certainly hadn't sent probes there. In fact, given how little they had to go on it was impressive they came as close as they did.
Now, technology of the future isn't the only thing that older science fiction movies occasionally tend to make mistakes about. Another area that also can make the experience of watching an older science fiction movie, especially one from the 1950's, to seem particularly jarring is the failure to predict certain changes in society.
Recently, we had the success of Gravity, a tense, critically acclaimed science fiction thriller centered almost entirely around a female astronaut. These days, most astronaut movies, barring historical films like The Right Stuff or Apollo 13, usually tend to have a reasonably co-ed crew aside from a few rare exceptions such as Moon.
The idea of an astronaut being stranded by themselves in space had been used before, but was usually done with a man, as is the case of Sam Bell in Moon or the earlier example of David Bowman in 2001: A Space Odyssey.
However, things were a bit different back in the 1950's, and if you look at older stories of space exploration, you see very different casts in many cases. To bring up an icon of the genre from that time, Forbidden Planet opens with a narrator hastily explaining mankind's achievements, talking about how men and women would land on the moon in the 90's (which oddly enough, might be seen as slightly ahead of us, since even today we've never actually put a woman on the moon) and begin travelling through interstellar space by 2002.
They do say men and women, so that all seems well and good, like there's some reasonable gender equality in the future. Then we see the group of characters who will serve as our protagonists: a massive expedition crew that happens to be made up entirely of white American men. My guess is that I may have misunderstood what they meant by "men and women" going into space, and what they probably meant was women going into space colonies established by the men to get married, likely acting as a woman would have been expected to in the 1950's, as opposed to men and women both going out to explore space together.
Indeed, a lot of old science fiction stories tended to have all-male expedition crews. You can see this very clearly in a ton of Ray Bradbury's older short stories (The Illustrated Man is an anthology that contains several examples of this), along with movies like Forbidden Planet. Now, female astronauts weren't completely unheard of. They did pop up from time to time in films like The Angry Red Planet or Rocketship X-M.
However, let's take a look at some of the better remembered science fiction of the period. Rocketship X-M does have a certain fanbase but we can't forget it was hastily put together to compete with the blockbuster Destination Moon, which also happens to be one of the first science fiction films to attempt to be as realistic as possible. Naturally, this resulted in having the narrative center around four men.
Later on, George Pal made the 1955 film Conquest of Space which talked about "men" building the Wheel. We naturally see an all-male crew, along with a massive number of people aboard the Wheel and no women among them. In short, according to this film, along with Destination Moon, Forbidden Planet, and various short stories of the early 20th century, female astronauts don't exist.
2001: A Space Odyssey was slightly more lenient, having been made while the women's rights movements were really taking off. It was also released only a few years after Valentina Tereshkova became the first woman in space, disproving the earlier depictions of all-male crews (though America didn't launch its first female astronaut until 1983). As a result, female astronauts do exist in Kubrick's world. In fact, we see Dr. Floyd have a short conversation with a group of four astronauts, only one of whom is a man.
However, even then it's still a very masculine vision Kubrick has of the future. Outside of the scene where Floyd talks to these three women (who curiously enough, happen to be Russian, perhaps something to do with the nationality of the first woman to go into space), there are women among the extras in the briefing scene at Clavius.
However, the rest of the women we see are in more stereotypically feminine professions. The most obvious would be the stewardesses seen on the shuttles to the space station and the moon, but we also see women working as secretaries aboard the station and the first line of dialogue in the film is spoken by a female lift operator.
While there are women visible in the briefing scene at Clavius, it is still the men who do all the talking. Later on when Floyd is taken on an expedition to see the greatest find of modern science, he is also in a group made up entirely of men.
This in turn brings us to Discovery, wherein the active crew consists of two men with another three in hibernation. At this point the only woman to appear is Frank's mother in a transmission. Now even today with a crew of that size it's not inconceivable that a mission like this could still consist entirely of men (although it would be less due to any prejudice of the time and more just a case of it being a small group of people and all the individuals who best fit the strict requirements for the crew just happened to be men), but it is still worth noting that there is no obvious indication of any women being involved. To be fair, though, the less popular sequel 2010 does have a strong female lead among the crew, and the Arthur C. Clarke novel it was based on actually had several major female characters.
Natalie Rae Wass in the role of David Bowman for the stage version of 2001: A Space Odyssey. Yes, apparently that exists. You can read about it here.
Even Carpenter's 1974 film Dark Star opted for an all-male cast, though again it is small enough that it isn't too far-fetched even today. However, the opening crawl does use the term "men" in reference to the crews of ships like Dark Star.
If I were to make any sort of guess, I would say the movie that finally changed it all would be Alien. The women's rights movements were finally getting somewhere in the 1970's and Ripley just happened to be a very good, strong female lead for the time period. Much like the Hawksian woman, Ripley was just one of the guys, but this time she didn't get a central romance, and of course she ultimately had to defeat the alien single-handedly after it killed everyone else in the crew.
Thanks to Ripley, most modern science fiction, barring rare exceptions like Moon (where Sam Bell was the only crew member) usually tends to have much more gender diversity in its cast. Stories of space exploration are no longer about "men" journeying to other worlds, but about "men and women" venturing outwards to explore the solar system and beyond.