Sunny Outlook for Sunsats

By Frederic Golden

A federal study finds solar satellites technically feasible

It is the year 2005. At the White House an agitated aide rushes into the Oval Office with grim news. "Mr. President," he announces, "OPEC has just raised its prices by another 10%, and oil will be going up to $450 a barrel by next January." To the assistant's surprise, though, the Chief Executive seems unconcerned. "Don't worry," says the President. "This time it isn't going to matter. We will have another three solar satellites on line by early next year, so we can tell those cartel characters to take their oil and [expletives deleted]."

Any scenario calling for complete U.S. freedom from foreign oil supplies is probably a petro-pipedream. But the notion of using solar satellites to capture vast amounts of energy may not be very farfetched at all. In spite of considerable scoffing at the sci-fi grandiosity of the idea, a report published last week, after a threeyear, $19.5 million study undertaken by the Department of Energy in collaboration with NASA, indicates that there are no insurmountable technological hurdles in the way of solar power satellites (SPS) as a major alternative energy source.

The report, says SPS Pioneer Peter Glaser, "is a landmark study that should go a long way to dispel the apprehensions and just plain misunderstandings about solar power satellites."

Glaser, 57, a vice president at Arthur D. Little, Inc., the Cambridge, Mass., consulting firm, is a Czech-born engineer who first proposed solar satellites twelve years ago. Foreseeing a day when oil would run out and other fossil fuels would become scarce, he suggested placing two giant arrays of solar cells, each about half the size of Manhattan, 22,300 miles above the earth in geosynchronous orbit; there the structures' orbital speed would match the planet's rotation, thus holding the solar powerhouses over the same spot on the ground. Bathed in almost perpetual sunshine, the cells, like those already used to power weather and communications satellites, would convert the sun's energy into electricity, which would then be beamed to earth as microwaves.

Even at night or on cloudy days on earth, when ground-based solar collectors shut down, these microwaves would come flooding down from space. In the scheme studied by the Energy Department, these beams would be focused on six-mile by nine-mile oval-shaped receiving antennas called rectennas. The rectennas would turn the microwaves back into electricity and funnel it into utility power grids. By Glaser's calculation, one satellite could supply as much electricity as five nuclear plants. The Energy Department envisioned 60 such arrays, built over 30 years, to supply 300 million kW., which is about half the U.S.'s current electrical generating capacity.

For a long time, Glaser recalls, even some of his scientific colleagues "thought T was writing science fiction." Many critics, recoiling at the potential cost of $100 billion or so for the first satellite, called his idea a pie-in-the-sky space boondoggle. Others worried about the effects of microwave radiation, fretting that passengers in passing airplanes might be flash-cooked like roasts in a microwave oven.

At a press briefing heralding the Energy Department study, Glaser replied to all these objections. He pointed out that solar satellites, unlike power plants that would use nuclear fusion, need no major technological breakthroughs; the space program has already shown that the required scientific know-how exists. What of the staggering costs? Glaser argued that after the turn of the century, when such satellites could be in operation, their electricity probably would be no costlier, and perhaps a lot cheaper, than power from oil, coal and nuclear plants. As for the danger from microwaves, Glaser conceded that this needs further study. But he pointed out that a satellite's beam would always be locked on target; in fact, it would disperse altogether if the satellite did not receive continuous electronic cues from a transmitter in the rectenna. Along its edge, said Glaser, the beam would be much less powerful than permissible leak age from a closed microwave oven.

For all the optimism radiated by Glaser and the Sunsat Energy Council, a coalition of individuals and corporations lobbying for his scheme, no one could deny SPS's enormous complexities.

Weighing up to 50,000 tons apiece, solar satellites would have to be built in space itself, with materials carried aloft by a new generation of craft considerably larger and more powerful than the NASA space shuttle. Looking like great Erector Sets, the structures, about six miles long and three miles wide, would be made of long thin beams actually manufactured in space out of rolls of aluminum or carbon-fiber strips about as thick as the wall of a beer can. In the weightlessness of orbit, nothing stronger would be needed.

Though much of the assembly would be automated, as many as 600 construction workers would have to be housed at the orbital site for months at a time. As NASA's problems with the space shuttle's heat-shielding tiles have shown, countless un expected difficulties could crop up in such a complicated undertaking.

Nonetheless, the House of Representatives was sufficiently fascinated by the proposal to pass a bill last year calling for $25 million in fiscal 1980 for further study of the concept, especially its environmental effects. Though the proposal died in the Senate, SPS advocates are now mounting a campaign for enactment of a similar measure by the next Congress.

They have one compelling argument in heir favor. This year the lawmakers passed a bill calling for $20 billion in spending for fusion research over the next two decades. Why not hedge that bet with a few million dollars at least to investigate another idea that may be every bit as promising?

-- By Frederic Golden

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