Space for another try

Soothsayers are vigorously looting archives. They are seeking part-loony and/or part-prescient answers produced for the problems raised by successive energy crises and climate-change scares last century. I mentioned one revivalist cry recently (MPS September 2009). The cause was the geothermal energy option. Agreeing that this had become a rather neglected subject I recalled the lament of one of its prophets. His opinion had been that the vast expenditure on probing outer space would have been more usefully directed downwards, into our planet’s interior.

I guess that to be a minority view. And space is still the winner, even among revivalist calls in today’s context of environmental and energy crisis. A case I have in mind has had a page-dominating feature devoted to it in a UK national newspaper – The Guardian – which splashed the story under the headline, ‘Space, the final frontier . . . and California’s latest source of low-carbon electricity’. The narrative (by the paper’s US environmental correspondent) reported the Pacific Gas and Electric Co’s benign view of ‘a startup company claiming to have found a way to unlock the potential power supply in space’.

There is acknowledgement in the article that ‘Nasa and the Pentagon have been studying the technology since the 1960s’ and that a James Bond film has been inspired by the concept, but truth is apparently going to beat fiction on this occasion in about 2016. Then Solaren Corporation – no longer a mere startup company – will consummate a recently done deal: PG&E will ‘buy 200 megawatts of electricity’ [sic] from the no-doubt-beaming vendor.

Unexplained is what makes Solaren et al so confident of outsmarting their predecessors. My understanding is that, nearly half a century ago, a visionary researcher named Peter E Glaser, while in the employ of Arthur D Little Inc, suggested the idea: and that it was studied in detail by Boeing Aerospace Corporation. Broadly, the proposal was to assemble in space, at an altitude of 40 000 km, a 50 km2 ‘island’. This satellite would be kept in position over a defined spot on the earth’s surface and be oriented to collect all the available sunlight. Solar cells or closed-cycle gas-turbine generators would use the energy to supply electrical power for production of a microwave beam aimed at a terrestrial receiver, possibly a 2 km-diameter dish. The output would be power for distribution to customers within range.

Thus would the intense solar radiation available outside the earth’s atmosphere be utilised for commercial power production on the ground. This entire seeming fantasy, the Boeing team thought, could be made reality with existing technology to start with, and thereafter with technology that was within sight, or nearly so. The researchers believed that at least one space-island plant could be ‘afloat’ and at work before the end of the twentieth century.

The Boeing enthusiasts argued that their scheme would be able to function very efficiently using microwaves of about 10cm wavelength, which would pass through the atmosphere with small losses on the way. They estimated that 13.5 million kW could be input by the beam to plant at ground level to yield a useful ten million kW for the grid. Of course they looked ahead to more than one island. They suggested about thirty for the long run.

Many possible hitches were imagined and considered. Typically, microwaves were recognised as potentially harmful to living

matter; so beams of them might conceivably stray dangerously out of control – or be used destructively with evil intent* (as fictitiously were death rays in the Bond film) – but engineers (as ever) were confident that they could design such hazards nearly-enough out of the system. Catalogues of catastrophe were compiled but the phrase that the project promoters kept on using as they shot objections down was ‘so that isn’t a showstopper’. Those were the days before ‘carbon’ had loomed up as an overwhelming menace. Figuring prominently among the ecological risks perceived then was harm to biota caught in the microwave beam. Maybe that hazard, together with daunting costs, was the showstopper that won the day.

Only in the Guardian feature’s headline is the ‘carbon’ demon mentioned.

Undeniably, rocket motor technology has, like power beaming, moved on in the last few decades – space shuttle craft get along for a while burning hydrogen rather than hydrocarbons. But I would not care to guess at the long-term nature and distribution of all combustion products from so much rocket traffic. Could space-island power stations indeed be assembled, run and maintained to contribute to relatively ‘low-carbon’ electricity supplies for earthlings? If so, perhaps Solaren Corporation will lift the curtain on this great show. The angel** will have to stump up only ‘the low millions of dollars in investment’, believes the startup company's founder.