In the opening years of the space age - from 1958 to 1970 - US satellites suffered 1,230 technical problems. It is now estimated that some 45 percent of those malfunctions could have been fixed in orbit, had astronauts been able to make service calls.
Such service is one of the benefits that US space planners envision as a new era of manned spaceflight develops over the next 10 to 15 years. This is the era in which the planners expect the United States to lay down the first elements of a permanent infrastructure for using near-Earth space in a routine way. This probably will be done in partnership with at least Japan and some European nations.
The National Aeronautics and Space Administration (NASA) is scheduled to try its hand at satellite servicing next April. Then it hopes shuttle astronauts can repair the Solar (sunspot) Maximum Mission (SSM) satellite that has been crippled by loss of its attitude-control system since October 1980.
But there is much more to the space planners' vision than making service calls. As the shuttle's ability to remain in orbit is extended to 30 or even 90 days, they expect manufacturing of pharma-ceuticals and perhaps semiconductor materials to begin. This could be done on the shuttle or on free-flying unmanned craft that astronauts could tend. Eventually, in the next decade, the planners expect some sort of permanent space station to be the hub of a network of free-fliers and other satellites, while also offering a laboratory for space research and equipment development.
Such is the vision that underlies NASA's conclusion that laying down this infrastructure and building a space station is the next logical and desirable major step for manned spaceflight.
As outlined in the first article of this series, critics such as the congressional Office of Technology Assessment (OTA) say they believe the United States needs a clear sense of what it wants to do in space before committing itself to anything as ambitious as a space station. Yet even such criticism focuses on the choice of projects, the speed of development, and the amount of money to spend. No one knowledgeable about spaceflight appears to doubt that humanity is indeed entering a new phase of this portentous activity.
This is already showing up even in the design of satellites. If astronauts are to service equipment in orbit, this must be made as easy as possible for them. Thus NASA has already introduced a standard modular satellite design, adaptable for different purposes. Malfunctioning parts can simply be pulled out and replaced by new units. The SSM and Landsat-4 Earth resources satellites (both of which have malfunctioned) are the first such vehicles. Among satellites yet to be launched, the Gamma-Ray Observatory, a Landsat backup, the Upper Atmosphere Research Satellite, and Fairchild's Leasecraft - a communications satellite for hire - share the modular design.
NASA administrator James M. Beggs says he believes the concept of in-orbit support and servicing (including satellite refueling) will open new possibilities for useful space applications that can only partially be foreseen today. It is a concept, he says, which will be fully implemented when a space station makes such servicing constantly available.
He explains: ''We feel strongly that the space station is a desirable next step primarily because it provides the means to open a lot of other options. It allows us to put a research center up in space. . . .
''It will provide an easy way that business can go up and work and test out any commercial ideas that they may have. But more important, it will allow us to operate more sophisticated scientific equipment because we can man-tend it . . . [We can] experiment in space, start to make real time analysis in space.''
Mr. Beggs acknowledges that some scientists are skeptical of his dream. They fear that a space-station project might drain off funds that could have supported more unmanned space exploration. However, he says he believes even skeptical scientists will come to see that ''we will realize the full benefits from our space research by getting up there and actually working, experimenting.'' This will begin with the shuttle. But it is the space station, where scientists and others can stay for several months at a time, which will offer the fullest space research opportunities, Beggs says.
For its part, the US business community has yet to appreciate fully the commercial opportunities that the shuttle and tendable satellites, let alone a space station, have to offer. Isaac T. Gillam, NASA associate administrator for plans and policy, says the agency has much missionary work to do in the business community at large, if these opportunities are to be identified.
The aerospace industry, which is familiar with space, is another matter. Here there already is some strong interest in a space station. The Center for Space Policy notes in a study released earlier this month that ''most operations in space would benefit from a permanent base in low Earth orbit. . . .'' The study explains that industry needs the assurance and support of a substantial federal commitment to leading the way to space commercialization. It sees a space station as an essential part of this commitment. ''Trade,'' the report quips, ''will follow the flag. . . .''
NASA's Space Station Task Force is a little more than halfway through a three-year study of what it calls a relatively modest concept. It envisions a program costing $4 billion to $6 billion that would evolve from progressively advanced use of the shuttle to the first small true space station. This would be in orbit by 1991 or 1992, in time to help celebrate the 500th anniversary of the discovery of America.
OTA's space station study group considers NASA's concept half-baked and lackluster. Project director Thomas F. Rogers told Congress last month that NASA thinking has taken place ''in a context of an inhibited and [perhaps therefore] relatively uninspired study.'' He added, ''Essentially, this study simply identified scores of ongoing activities, i.e., 'missions' and already planned activities that [they hope] would receive approval.''
He warned Congress that the planning seems so fuzzy that ''there is no single thing called 'the' space station.'' Instead, he said, ''the cost could be as low as $5 million for the smallest passive platform, to hundreds of millions of dollars for a shuttle orbiter modified to allow a considerably extended lifetime in orbit, to tens of billions of dollars for sophisticated, essentially permanent, elements that could support a large crew and a wide range of activities.''
NASA officials admit that they had felt inhibited by lack of encouragement from the administration. But this year that attitude has changed. Presidential science adviser George A. Keyworth II has even criticized NASA for not being imaginative in its planning. NASA administrator Beggs says he believes the administration's mind-set against new space initiatives is shifting. And NASA planning, he says, will respond.
Beggs also disputes the notion that space station development will be excessively costly. He says what NASA needs is continuity of funding - without arbitrary annual ups and downs - not a massive amount of extra money.
He explains: ''If this agency could expect to be able to spend 1 percent of the federal budget for the next 10 years - much better if the next 20 years - we could double the achievements of the last 25 years, because we could then lay the long-range plan and start moving up the ladders rung by rung in a logical, progressive fashion.
''One percent this year would be about $8.5 billion, whereas we're spending $ 7.2 [billion]. So it's not all that much money. Even if we were spending a little less than that, if we could count on $7 [billion] to $8 billion, we could do an awful lot.''
Whether or not Beggs will get the kind of long-term funding he feels he needs is hard to foresee at this point. As the OTA has noted, there does seem to be a need for a national debate and for leadership from the administration to get the United States moving decisively toward new space goals.
On the other hand, the US space program does seem ready to produce the vision sketched by OTA director John H. Gibbons, who says: ''The space area may gradually become simply one more place where commerce, manufacturing, and perhaps even the arts and the humanities will be carried on. The question of whether to conduct a given activity in space or on the ground will increasingly become simply one of relative cost and convenience.''