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Comment by inasio | Hacker News Reader

“It’s a lot easier to send a power beam directly up or down relative to the ground because there is so much less atmosphere to fight through,” Jaffe explains. “For PRAD, we wanted to test under the maximum impact of atmospheric effects.”

Super impressive! My only complain is that this was done at the White Sounds desert in New Mexico, at over 1200 meters of elevation. For maximum impact they should have done it in Florida on a hot humid day

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Humidity would most likely attenuate the beam from 20% end to end to less than 1% - water vapour absorbs energy like nobody’s business.

This is a tech for arid environments - which seem to be where the US does most of its deployments these days.

There’s no range in Florida large enough for this test otherwise I’m sure they would have.

Even Eglin wouldn’t be large enough.

＂maximum impact of atmospheric effects＂ would be simply a foggy day...

Both your example and theirs would be better tests than a desert.

The desert is bad enough. On a hot day you get convection which will vary the refractive index of light and spread out the beam. I wonder if they have active optics on the transmitter to fight this.

Then you also have the day vs night weather patterns, resulting in intense sun-downer winds. I suggest everyone actually visit a real desert once in their life, where as people seem to think its like a beach, but bigger.

Around Elephant Butte Lake which is quite close to WSMR [1], I remember those really strong winds around sunset.

[1] https://en.wikipedia.org/wiki/Elephant_Butte_Reservoir

The US is always geared up and ready to fight the previous war.

Unless, you know, we often fight in deserts that are remote?

This is a good point. I just meant that a very humid climate might be a more challenging environment for this technology, but it doesn’t mean it’s as useful for real world fighting conditions.

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