IT WILL BE a while before we see ads on the home screen for Special Supersaver Space Shuttle roundtrip fares from National Airport to Solar City and points outward, but space travel itself is become marvelously less extraordinary with the passing of each day and mission. It's not that today's astronauts are less challenged, or that people aren't relieved when a mission ends safely; there are dangers always, and each mission presents new challenges. The difference now is that getting there is only half the fun; the people who are going along and what they're doing as they go is what is making the space program a more impressive investment.

For starters, there are the crews: nobody really gives a second thought now to the fact that men and women, black and white and older than they used to be, are taking off, doing their duties and holding up well, thank you. (Surely it's only a matter of missions before we see "infants ride for free".) And though these crews still run into troubles along the road, the way they cope sounds more and more familiar. Ice outside the vehicle? First you try hot water, and then stick out a mechanical arm and knock it loose. Had that not worked, get out and start scraping.

Far more fascinating are the experiments going on in space. During last December's Spacelab mission on the shuttle Columbia, there were all sorts of significant activities taking place. Science magazine reported a total of 72 experiments. There was the metric camera, for example, which photographed more than 7 million square miles of the Earth from space, providing high-quality, first-time images of many of the world's regions. There were stars being seen for the first time, too.

Studies of materials in space also are leading scientists in many new directions. Silicon crystals, important in electronic components, have been grown three to four times larger and purer than any grown on Earth, experts report, as well as two human proteins that may assist research in treatments for disease. The mission now in progress is supposed to include an experimental drug-manufacturing unit. And there has been the deployment of a special solar panel as part of a program to provide power for tomorrow's space stations.

It is true that a lot of money is involved here, but the early simplistic critics who characterized the space program as wasteful joy rides stealing money from the needs of earthlings may now at least note that the some of the world's toughest battles -- against deadly diseases -- may be won in laboratories beyond their local beltways.