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Submission + - Inexpensive exotic metals (economist.com)

carstene writes: AL was once more expensive then gold, until a process was invented to separate it from its oxide electrically instead of chemically. A company in the UK, now claims to of done the same with tantalum, reducing its cost by an order of magnitude. The process can also work with other exotic metals such as titanium.

Comment Re:How is this better than a balloon? (Score 2) 103

Balloons get really big fast as you add payload. This means that more and more of your energy is used for station keeping rather then payload. Also with the UAV solution it is small and light enough to say fit in the trunk of a car and be handled by one person. For a balloon to carry any practical payload it is large enough where one person can no longer handle it on there own.

Comment Re:Old idea, commercially available now (Score 1, Informative) 103

Main advantage of fiberoptic is two fold, first it is lighter then copper per unit of energy you can push through it. Second it is has no electrical resistance, so you don't get a huge voltage drop over long distances. What this means is you can have more payload at greater height then with a copper based electrical solution.


Mars Images Reveal Evidence of Ancient Lakes 128

Matt_dk writes "Spectacular satellite images suggest that Mars was warm enough to sustain lakes three billion years ago, a period that was previously thought to be too cold and arid to sustain water on the surface, according to research published today in the journal Geology. Earlier research had suggested that Mars had a warm and wet early history but that between 4 billion and 3.8 billion years ago, before the Hesperian Epoch, the planet lost most of its atmosphere and became cold and dry. In the new study, the researchers analysed detailed images from NASA’s Mars Reconnaissance Orbiter, which is currently circling the red planet, and concluded that there were later episodes where Mars experienced warm and wet periods."

Submission + - NASA Power Beaming challenge is on for November 2

carstene writes: The NASA Centennial Challenge Powered Beaming competition, to develop technology for uses such as a space elevator, or to power a rover in a shadowed creator on the moon, was delayed indefinitely due to trouble setting up the kilometer high race track. It has now had the kinks worked out and is rescheduled for the week of November 2nd. The competition involves using a high power laser to beam power to a robot that climbs a kilometer high cable attached to a helicopter. You can follow the competition at the organizers blog. I'm a member of Lasermotive team, one of the 3 competing. The competition was previously covered on slashdot.

Comment Re:Sterling Engine (Score 1) 98

A diode laser, like we are using is also about 50% efficient in turning electrons into photons, so under ideal conditions you get around 25% of the electricity out the other end that you put in. I will point out that you still have to heat the Stirling engine with something like a laser so it has exactly the same lose on that end as beaming to a PV does.

Comment Re:Microwave instead of visible energy (Score 3, Informative) 98

Turns out that divergence is set by the wavelength, larger the wavelength the bigger the minimal divergence. Check out http://en.wikipedia.org/wiki/Diffraction-limited_system . Our lasers wavelength is 808 nanometers. Compare that to say 1 centimeter for microwave and you can see that microwaves will always require a much bigger "lens/mirror" to focus them.

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