Aboard a space station mock-up
ALBERT Wetterstroem moved quickly among several computer screens. On them were images of the power supply of a mock space station, shown with varying degrees of detail.
Reaching toward a schematic diagram of a fuel cell, he touched the symbol for a valve. Immediately the computer showed the valve opening. The pipes it connected turned from orange to green to indicate that fluid was beginning to flow.
One could easily imagine an actual valve also opening as an astronaut on a real space station adjusted its systems.
Here is a new way to control equipment. Instead of throwing switches, you manipulate symbols on a computer screen. Instead of thumbing through bulky manuals or stacks of cue cards, as shuttle astronauts do to find the proper procedures to follow, these are programmed into the computer representations.
In the Space Station Command Center Mock-up at the Johnson Space Center the process still is make-believe. It is an imaginative taste of the future with which project director Wetterstroem hopes to learn something of what astronauts will need on a real space station in the next decade. ''We're trying to become smart buyers,'' he explains, trying to learn what to require or accept from industry and what to turn away.
The National Aeronautics and Space Administration needs to be a savvy shopper. It is ready to start an $8 billion space station project with $150 million for initial studies in the fiscal 1985 presidential budget. Would-be contractors already are polishing their proposals.
Yet, as Wetterstroem ruefully points out, until Congress actually appropriates some money, the space station remains an unfunded program. Thus his mock-up project here is a low-budget operation that has had to make the most of scrounged equipment and borrowed parts. However, together with Greg Blackburn and James Duron, who wrote most of the software, Wetterstroem has put together a simulation of what it might be like to control a space station electronically.
The mock-up is arranged as a dual-position work station where two astronauts can work side by side. In orbit, they would float weightlessly - held in place by belts, foot restraints, or handholds. Each position has several computer displays to work with. These can show several elements simultaneously - different levels of detail of a system, different systems, even the station's orbital track over Earth below.
Wetterstroem explains that the essential concept is that astronauts use the computer power, which the displays represent, to interact with a data base and, beyond that, with the actual physical systems of the station which they must adjust and control. These systems can put information about their status into the data base, which is essentially a well-organized library of information in computer-accessible form. They can look for commands in it and react to them. Likewise, the astronauts can read out information from the base and put commands into it to control the equipment.
The result is that space station astronauts can interact with the representations of equipment on the displays and manage the station systems without having to know in detail how those systems operate. That information is in the data base and is incorporated into the system representations. In the case of the mock-up here, the actual station equipment is simulated by mathematical models programmed into the computer system.
There will be many different types of people on a space station who cannot be expected to be expert in station hardware yet who will have to use it. This contrasts with the shuttle astronauts, who are given detailed training to understand the systems they must work with.
Wetterstroem notes, however, that if this concept is to mature into a practical way to manage a space station, it first has to be thoroughly worked out and tested on the ground.
''If you define the problems on the ground, it's a lot cheaper than trying to fix them in the sky,'' he observes.
That is what the project is beginning to do in a small way.
''We just put ideas out here,'' Wetterstroem notes, ''and then, eventually, people will start putting these ideas into requirements.'' It is this kind of practical make-believe - this kind of advanced exploration - that underlies much of the success of the present shuttle program.