NASA Flies First Laser-powered Aircraft

unassimilatible writes "NASA has successfully tested a small-scale aircraft that flies solely by means of propulsive power delivered by an invisible, ground-based laser. How far away can in-flight IP/LASER broadband be?"

We did this in Canada 15 years ago...

[Recoil_42]

or something like it:

It used microwaves [friendsofcrc.ca] instead of "invisible lasers" (IR? i havent RTFA yet) but same end result, no?

Not a laser..

[Anonymous Coward]

When was the last time you saw an invisible laser.. lasers are in the visible light spectrum.. this is scalar energy.. nasa has finally woken up..

too bad the soviets were dealing with this stuff in the 1950's..

http://www.cheniere.org/books/analysis/history.h tm

Re:Life Imitating Art?

[orthogonal]

building humungous lasers in their asteroid belt and planet surface, and using them to propel a light sail armed interstellar craft between stars.

IANAP (I am not a physicist), but isn't using light pressure in a vacuum to drive a light sail entirely different from an aircraft with "specially designed photovoltaic cells carried onboard to power the plane's propeller"?

It's like (poor analogy alert) saying that a gasoline powered car and a squeeze-jet that squirts out liquid gasoline to propel itself through the water are using "the same" propulsive technology.

BTW, light sails were proposed by real physicists long before Niven and Pournelle wrote the excellent Mote in God's Eye.

Re:Not a laser..

[YouHaveSnail]

When was the last time you saw an invisible laser.. lasers are in the visible light spectrum

I'm not a physicist, but I've seen lots of inivisble lasers (okay, not the beam itself, but you know...). Lasers in both the infrared and ultraviolet regions are commonplace. Google for "infrared laser" or "ultraviolet laser" and you'll find many, many examples of each.

I suppose you could make some sort of argument that the L in LASER if for "light," and that IR and UV somehow aren't light because we can't see them. But insects and perhaps some animals can see in those regions, so it'd be a difficult position to defend. Both IR and UV are called "light" in general use. Additionally, there's no significant physical difference between a visible light laser and a UV or IR laser. And scientists now use the term "laser" even where most people would agree that the electromagnetic energy in question falls outside the part of the spectrum that we tend to think of as "light," e.g. x-ray lasers [optics2001.com] and microwave lasers [achilles.net].

A Few Comments

[ChuckDivine]

I first read about this sort of thing back in the 1970s. Proposals back then focused on constructing huge satellites (think 5 miles by 5 miles or 10 KM by 10 KM) in geosynchronous orbit. Energy would be beamed to earth via microwaves or lasers.

Planes could be powered via laser pointed at various reception devices (photovoltaic, steam generators, etc.).

Clouds would not be a major problem. Just pick a frequency that penetrated the clouds fairly easily. Or, in the case of airplanes, fly above the clouds.

For lots more information, just Google "Space Solar Power" [google.com].

Some old articles...

[stevesliva]

I remember several visits to RPI where research into this was touted, and I think that was around 1997.

• Google Search [google.com]
• 1998 Article [manufacturing.net]
• 1999 Article [nasa.gov]
• 2001 USA Today Article [usatoday.com]
• 2002 NYTimes Article [uah.edu]

Re:Why can't they do this with power?

[WolfWithoutAClause]

The sun only has an intensity of about 1KW/m^2m, whereas lasers are up at ~100MW/m^2.

Also, solar panels are only about 5-15% efficient. That's because they only absorb certain frequencies of light, and the other frequencies that the Sun presents is wasted.

However, if you point a laser at one, they're much, much more efficient (>50%). That's because you can choose the laser to match the solar panel.

But the big problem with laser power beaming is stuff like clouds, and fog...

Re:Not a laser..

[Pooua]

When was the last time you saw an invisible laser

Well, if it is invisible, by definition I could not see it...

lasers are in the visible light spectrum

I have an Associate's Degree in Laser Electro-Optic Technology. Any oscillator that produces electromagnetic radiation in the range of infrared or shorter wavelengths by the process of stimulated emission of radiation is considered a laser. In fact, the name has become shorthand for just about anything that produces a beam of anything through quantum triggering (e.g., an "atom laser [mit.edu]"). A carbon dioxide laser's primary (strongest) output wavelength is 1.6 microns, which is well within the infrared portion of the spectrum, and completely invisible to the human eye. The Nd:YAG laser also produces its primary wavelength in the infrared range (the beam is often sent through a frequency doubling crystal, which produces green light at half the power of the input beam). CD players use an infrared diode laser (invisible beam). At the other side of the visible spectrum, the eximer laser produces ultraviolet light, at a wavelength that is invisible to the normal human eye. The nitrogen laser also produces a beam that is not directly visible to the unaided human eye, but the beam causes air to fluoresce in a wavelength normally visible to humans.