16Photovoltaics Bulletin August 2003

COMMENT

We begin this month’s column with a fewremarks about earlier news items. On ahappy note, the trio of Mars probes arenow all on their way, after some delays. Wecannot, however, uncross our fingers justyet. The Beagle 2 mission has been causinga few anxious moments. The power systemhas registered low voltages, but instru-ments on board are now said to be workingwell. Nevertheless, data have been receivedfrom the Omega spectrometer, whichdetects constituents of Earth’s atmosphere.By way of confirming the value of themission, new photos of the Earth andMoon have been sent back. Missioncontrollers can point the spacecraft’s high-resolution stereo camera during instru-ment checks, and gave us some superb truecolor images, revealing the blue PacificOcean and white and grey clouds. Itprovides a taster of what we can expectonce the spacecraft is in orbit around Mars– high-resolution images with brillianttrue color and in 3D.

The bad news from the leading edge ofunmanned PV development has been the lossof the Helios solar aircraft. Previously wereported some problems, but when we leftthe story further flights were imminent. Bythe time this issue was being compiled theseproblems should have been behind them. Asno doubt you have read elsewhere, Helios didnot reach its full altitude but was lost. The$15m Helios Prototype crashed near the USNavy’s Pacific Missile Range Facility atBarking Sands, about 30 min after taking off.Worse still, bad weather meant that thewreckage was scattered. As a result it lookslike all of its precious solar cells were lost. Itwas also testing an experimental fuel cell/electrolyzer system in preparation for a long-endurance mission of almost two days.

Another airborne mishap concerning solarpower was the escape of the ‘Flyborg’autonomous flying airship from the MagnaScience Adventure Centre in Rotherham,Yorkshire, UK. Aviation authorities had to beinformed after it floated off while beingmoved. Valued at £15 000 (US$23 000), theFlyborg is driven by propellers powered by abank of solar cells. It was designed by ProfessorNoel Sharkey and his team at Magna’sCreative Robotics Unit, for indoor flyingrobot exhibitions. The 13 foot (4 m) longairship can quadruple in usual size as itascends, and experts reckoned it could travelfor a week before deflating – meaning it mightend up somewhere in Europe. At the time ofgoing to press we were awaiting news of itsfate. An artificially intelligent flying robotairship filled with helium, the Flyborg isautonomous so it can avoid obstacles.Technicians moving the airship were caughtout by a gust of wind snatching it away.

Also on the subject of airships, a US-basedaerospace company is discussing with Indianscientists a collaboration for civil and militaryuses of airships. StratCom International andthe Indian Space Research Organisation(ISRO) and the Indian Defence ResearchDevelopment Organisation (DRDO) arelooking to exploit solar-powered airships fortelecoms, telemedicine, broadband commun-ications and disaster management. The firststratospheric airship prototype is being builtwith the support of the US Department ofDefense, which has invested $100m in theproject. Each airship should cost $20m, withan operating life of five years.

Another novel use of PV power is forelectrical supply to remote or independentelectronics systems such as surveillance of

potential terrorist targets. For example, theLexington Reservoir in California has recentlybeen equipped with a state-of-the-art camerafrom RVision. The small, solar-powered,infrared cameras cover large areas, like reserv-oirs, and are remotely controlled for 24-hourvision. The system can stream suspicious videoto a web-enabled PDA or cellphone. Thecamera has a motion detector to pan, tilt andzoom. The California Department ofTransportation recently awarded RVision acontract to supply hundreds of cameras andrelated equipment to secure the bridges andtunnels of the San Francisco Bay Area.

Finally, on a brighter note I have invested inmy own first PV equipment. I felt I couldhardly write confidently on the subjectwithout some form of PV supply of electricity.We are not yet ready for the full roofinstallation, but starting small, I now have aPV battery recharger. I can now make full useof fine summer weather to recharge batteriesfor my CD player. The results so far have beenmixed. My fairly cheap unit from Maplinseems to prefer new cells. Left in for a wholeday at peak British summer solar levels, someolder batteries lasted less than a full CD on myportable player. A lesson there for all of us –any system is only strong as the weakest link.If it stays hot the next purchase is likely to be ahat with a built-in PV-power electric fan.

Progress cannot proceed to best advantagein isolation. In the case of PV we must alsoperfect the batteries – they must work withthe PV cells for best performance at thelowest price. Add into the mix furtherimprovements in the equipment that will usethe recharged cells. My CD player is a decadeold, and a new one should use less power. Butany gains are often offset by added features.

Good news, bad news, one small step