It may be unmanned, but then again, the Wright brothers only remained aloft for a very short time. Symbolically I find these sorts of ventures very important, as they represent the beginning of new technologies coming into effect. I don't think the Wright brothers could have seen the A380 from where they stood, and we probably can't see a solar powered large jet from here, but this is as good a start as any!
It is not enough to be rude; one must also be incorrect.
Rwessel From United States of America, joined Jan 2007, 2740 posts, RR: 2
Reply 1, posted (8 years 8 months 3 weeks 14 hours ago) and read 2617 times:
Well, the problem is the density of solar energy. If you (very, very, very optimistically) managed to capture a quarter* of the 1365w/sq m solar flex at this distance from the sun, covering the entire (540sq m) wing of a 747 would generate the equivalent of about 4.5 gallons of Jet-A per hour. It's not a question of doing a better job - that's just all the energy (the 1365w) that's available.
*For starters, you've got the atmosphere attenuating things (at sea level by about 25% at noon, much more in the morning and evening, less at altitude), the fact that the best (and wholly impractical) multi-junction solar cells manage about 40% efficiency in lab conditions (and then only at much higher fluxes), and the minor detail that you're almost never going to get the solar array at exactly a right angle to the sun.