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Is a Laser Data Link 1.5 Million Kilometers Feasible?
An anonymous reader writes "On the Canary Islands last week, a team from Oerlikon Space demonstrated the feasibility of a laser link across a distance of 1.5 million kilometers for the first time ever. In the future, laser links like this one will be able to transmit data across huge distances through the universe far more rapidly and efficiently than is possible using conventional radio links today."
Who would have thought that light could travel such a long distance?
In all seriousness, the problem is not the knowledge a laser can travel that far; its whether you can create precise enough targeting equipment.
A radio signal might be more of a splatter, but at least if you point it "over there" with enough power behind it, it will get there.
As they say their simple hilltop to hilltop test failed because of weather conditions, whats going to happen when they do put 'scopes at the lagrange points?
"Oh sorry, we can't get the data today because its cloudy"
Back onto the radio front, we have Voyager 1 which is 15 billion miles away, proven with radio, that would seem good enough for me.
liqbase
"laser links like this one will be able to transmit data across huge distances through the universe" I think they mean "through the solar system"... laser wouldn't be very efficient "through the universe"... I think we may have other means of communication by the time we need to think about distances that vast.
Do not look into laser with remaining eye.
Hi,
It seems to me that this would be especially useful to reduce the amount of induced radio noise when communicating with L1 (etc) radio telescopes or other instruments potentially sensitive to the normal radio frequencies used for communication, eg keep the comms out-of-band of what is being measured as far as possible.
Rgds
Damon
http://m.earth.org.uk/
Canary Islands and experiments with laser beams? Ahah! There must be sharks there!
Do lasers follow the inverse square law? I'm guessing it doesn't since it's focused.
Either way, correct alignment seems pretty tough.
Gone!
Are there sharks there or something?
One of the biggest problems we'll run into with this is aiming the beam between the sender/reciever. 1.5Mil Kilometers is already enough of a distance, but we also have to keep in mind the fact that both ends will likely be in constant motion.
"I think an etch-a-sketch with an ethernet port would beat IE7 in web standards compliance."
Space sharks with frikkin' laser beams! They use lasers not to kill, but to coordinate with other space sharks.
Because lasers travel at least 42 times as fast as radio waves!
Where are the space sharks? We need them to help us with our laser issues!
They will all stop at the last mile, rendering the project useless.
Great idea, now try to do the math on all of the floating bodies and the effect of the gravity from neighboring quasars and other space phenomena.
I could see it working but the receiver would have to be huge. It's hard enough to hit someone with a gun at a mile using a laser sight (windage which would be comparable to space effect on the laser light).
Maybe a single shot of data, but maintaining that connection would be very difficult IMHO.
It's still a cool idea.
Super(luminal)!
Help! I'm a slashdot refugee.
Aren't there sharks out there? Hmmmmmmmm....
GetOuttaMySpace - The Anti-Social Network
Can't you also make a laser out of radio waves? I know they have microwave "lasers" called masers, so do "rasers" exist?
Laser beam has more bandwidgth than radio, but it still travels at the same speed (c).
And the distance mentioned (1.5 million kilometres) doesn't seem very useful. thats too far for the moon, but not far enough for Mars - theres nothing out there to talk to.
We recently had a laser link installed between two buildings here. 100 metres was the distance between them. The recent foggy mornings rendered them useless.
1.5 million kilometres? Good luck!
I was curious about the same comment, but they must just be referring to the higher bandwidth available at optical frequencies compared to radio frequencies. In other words, the latency would be the same, but once the first bit hits, you will get the next million bits "more rapidly" and the next trillion bits "far more rapidly."
The transmission unit was modified in such a way that the conditions on the 144-kilometre stretch between the islands exactly reflected those that would prevail on a 1.5 million kilometre link through space. This was achieved primarily by reducing the emission aperture of the laser to a diameter of less than half a millimetre in order to weaken the light signal. I have a hard time believing that a measly 144km stretch on a planet WITH ATMOSPHERE is able to exactly replicate the conditions of a 1.5 million km stretch of space. I mean let's look at the ozone. I'm not a scientist and I only hold a GED, but doesn't that thing block cosmic rays and radiation and shit? What would that do to a laser? And let's assume for a moment that they are just shooting from ship to ship. What about atmosphere? Would the laser require less intensity to be shot such a long distance due to the lack of interference from an atmosphere? And if so, wouldn't little things like the quality of technology have a greater impact on the quality of laser stream? I dunno. I see way too many holes in this to see any plausible correlation to 1.5km of space.
This is why project like SETI are bound to fail - the quaint 20th century notion of using diffuse 'broadcasting' of uncompressed, redundant intelligence (anything distinguishable from noise) using undirected RF energy in all directions is something the aliens abandoned millenniums ago, for more efficient point-to-point methods like this.
try { do() || do_not(); } catch (JediException err) { yoda(err); }
What the article doesn't mention is the poor crew that were huddled behind the massive metal crate up by the NOT (Nordic Optical Telescope) on these tiny little white plastic chairs (which had to be weighted down by rocks when they got up). I was up there at the WHT/NOT the other week and happened to pass by their setup, the only potential hint at what they were doing being one of those little yellow hazard signs that simply said 'Laser' on it. Glad they got what they wanted - the weather was pretty terrible for several days, you were basically sitting in cloud.
1.5 million kilometers = 1.6 x 10^-7 light year.
Distance to galactic center = 26,000 light years
Distance to nearest (Andromeda) galaxy = 2.5 million light years
"Faster than radio" probably refers to increased bandwidth, because light-speed is light-speed.
Would there not be major line of sight issues and percision issues. My crude understanding of radio waves is that you can send a signal across a wide area and it seems to me a laser would have to be more exact to get the data because of the shorter wave length. I see a shorter wave length as a disadvantage; especially over longer distances.
I hereby welcome you, Oerlikonians. But could anybody tell me where this Oerlikon space is and how Oerlikonians look like?
But seriously:
Now we only need to get something or someone that far away that it actually makes sense to drop radio waves for laser beams.
"Hannibal's plans never work right. They just work." Amy/A-Team
Farther... sure, because it's a focused beam.
But faster? Don't radio waves and laser beams both hit the same speed limit (the speed of light)? Radio waves are photons too.
The ability to encrypt nefarious messages in a death-ray across long distances.
Some popular messages include:
- "If you are reading this message, you are probably toast"
- "PWNED!!!"
- "(Scorpio) Avoid reading under strong light"
- "Knock, knock"
- "Is this the James Bond? Oh sorry, my mistake."
- "Can you hear me now?"
- "Special Delivery!"
- "Ceiling Cat sez hi!"
It seems strange that they didn't aim for the retro-reflector placed by one of the Apollo missions which has been used for 30+ years for laser ranging experiments. It's location is well known. That would give them a real 800,000 km beam path, roughly half of what they claimed.
I think the real question is whether or not LOS for 1.5km can be maintained on a constant basis..
So basically, -1 troll/offtopic is really slashdots way of saying "I hate that you thought of something before me."
You lights only go at light-speed? Pfft.
I don't recall the details bit I seem to recall astronauts putting a target on the moon's surface back in the '60s or '70s. The laser was a few feet or less in diameter when it returned to earth.
Knowledge is how to play a game, intelligence is how to win, wisdom is knowing what game to play.
I love this quote "The transmission unit was modified in such a way that the conditions on the 144-kilometre stretch between the islands exactly reflected those that would prevail on a 1.5 million kilometre link through space." And in a related story, a vast region of the Atlantic disappears from satellite view. Also, are we now quoting transmission speed in Bible units?
whats going to happen when they do put 'scopes at the lagrange points?
I've been thinking about the Earth/Sun Lagrange points lately. I think they might be an excellent location to test an Earth/Mars transit vehicle. ESL5 is far enough away to be out of Earth's magnetosphere, so it will experience the raw radiation environment. It would be able to remain in position for long periods of time. The only hitch I can see is it may not be easy to get to/from. I can't seem to find any data. If we put a test platform with a "lifeboat" craft there, how quickly could the craft get back here. Is it days away? weeks away? Anybody know?
When our name is on the back of your car, we're behind you all the way!
In the article, they say that the distance was chosen because it is the distance between the earth and either of the L1 or L2 lagrangian points. SOHO currently sits at L1 and talks to earth with a 200 kbit/s radio, so this isn't exactly a hypothetical scenario. (An interesting question in that case, though, might be whether we can reliably receive a laser signal against the sun's background radiation.)
Does anyone recall the story from a couple weeks ago about an autonomous Oerlikon machine gun killing 6 people at a demonstration in South Africa? I imagine these lasers will be lower power than to burn through objects, but perhaps it's a matter of time before high-powered space lasers come about (think 80s: Star Wars, Reagan-esqe). I hope they put more testing into these lasers than with their machine guns.
P.S. I currently work for Oerlikon Systems, (not Oerlikon Space (formerly Contraves Airspace)). Never thought I'd see this company get Slashdotted!
if the hot space aliens don't want you and your porn dvds were left on earth.
Just be careful to keep the aim right, you don't want to end up blowing up your power station and taking out a few blocks of your city...
Do not look into laser with remaining eye.
Correct, they did put corner cubes on the moon (aka retroreflectors, or three mirrored surfaces all at 90 degree angles to one another).
However, the beam size from a collimated laser is a couple miles across at the moon. Typically, receiving a signal back takes a large telescope which counts single-digit photon returns from a Nd:YAG q-switched laser. It's been almost 2 decades since I worked with the stuff (you might search for Satellite Laser Ranging, Goddard Optical Research Facility and MOBLAS or TLRS) and the units that ranged on the moon cubes were at Mt. Haleakala in Hawaii.
It was neat stuff, but I remember one of the PIs saying the spot on the moon was the size of Georgetown (a section of Washington DC), though I can't remember exactly now. The outgoing laser was about 4" in diameter.
Is it just my observation, or are there way too many stupid people in the world?
The ozone layer of the upper atmosphere really only filters out wavelengths of light that are less than 320nm or so (ultraviolet and higher spectrum). Most LASERS typically operate using wavelengths in the visible spectrum of light or infrared range.
bounced the signal off the reflector that Neil Armstrong left at the Apollo 11 landing site. Round trip could have come pretty close to 768,800 kilometers... bouncing it back up and down again would have made the link as near as damn it = 1,500,000 kilometers
Donald 'Duck' Dunn: We had a band powerful enough to turn goat piss into gasoline.
I remember this being done with Earth Observation satellites. The EO satellite beams data using an optical link to a satellite that is in geostationary orbit. This satellite then beams the information down through a microwave link. This frees the EO satellite (that producue huge amounts of data) of the need of high-power consuming RF transceivers, reduces the need for ground stations, and is seriously cool. This was done in 2001 between SPOT 4 and Artemis (Press release). Note that SPOT sits in an orbit around 800km, and Artemis is geostationary... They then did the same with an aircraft (see here).
So it is really quite useful. When you consider the amount of data the sensors on board ENVISAT (or even MODIS) produce, this is an important tool.
Perhaps - but on the other hand, its not like it will be easy to eavesdrop on. (almost) no divergence... you know that the only person listening is the person to who its directed.
I guess you could get _some_ info from diffraction (eg - metal powder), but at a much reduced intensity - and a resulting weaker signal.
The Bible: Historically verifiable fact from an observers point of view
This is just more proof of what we already know: that the tighter the beam the more efficient it becomes for point-to-point comms in terms of energy usage and overall loss/noise.
Its also something to think about with respect to SETI. I mean the universe could be swarming with life forms communcating over great distances, and it would make more sense than not that they use tight beams to do this. In which case SETI won't ever pick anything up because nearly all the energy from their comms is only going each other.
we have the Gas engine... it works.. lets forget about all this crazy hybird and electric car talk...
While we're at it, Coal Plants do a good job at producing energy and they work too... lets forget about all that fandangled alternate energy source stuff...
While were at it.. smoke signals work too.. no need for complicated technology like telephone and email...
okay.. now that my sarcasm limit has been reached... because something works is not a good reason for ignoring technology that can potentially supercede it...
If we start shining huge lasers into space, we're going to end up accidentally blinding aliens. Which might be good (if they're chest-explody types), or bad (if they're hot sex-starved space-babes). Your call.
Get your own free personal location tracker
Some guys in the US Army Signal Corps aimed their very primitive SCR-348 radar sets at the Moon, and wadda you know, an echo came back. All done with what looks like from now as very primitive vacuum tubes, diode detectors, and magnetrons.
A laser is just a Very high frequency radio transmitter. The latecomers just upped the frequency by a large factor.
The US has a several classes of Signal intelligence and Communication intelligence satellites. I would be shocked if they didn't already use an optical link to send their data to relay satellite for downloading to a ground station. An optical data link would make the satellite "silent" so their data link wouldn't interfere with there intercept receivers. Since both the satellites are in space you wouldn't need to worry about weather an since they are both in geostationary orbit you wouldn't need to worry about aiming. Of course the other benefit is that you could beam the data right from your recon satellite parked over Asia to a relay satellite parked over the US and then right down to a ground station in Virgina. No need to have a ground station in a friendly or not so friendly country.
See my blog http://ilovecookes.blogspot.com/ for light hearted technical information.
...that 10-second ping would be a killer for the gamers :)
...because I have so many files I need to trade with the aliens.
-- I am. Therefore, I think!
bet you feel like a total fucking fuckwit now, don't you, you patronising arrogant CUNT.....
I seriously doubt that sharks can survive in space for too long, and even if they could..it's exceedingly doubtful they would hold still enough to transmit data in this way. Get real.
Your point on aim is well taken. Also the rare chance of an obstruction along the path may prove an issue. A passing asteroid or a deliberately placed man-made object would effectively sever the link - at least close enough to the source such that the laser would not have scattered much yet.
What I don't get here is how a laser is going to make the communication any faster than any other form of electro-magnetic transmission.
-- What you do today will cost you a day of your life.
I am a moron when it comes to this kind of engineering, but couldnt they use a radio signal to get targetting information, i.e. a handshake then pass the data transfer aspects to the laser?
"sudo apt-get install foobar" scares non-techies. Say "Install foobar from Add/Remove (or Synaptic)" instead.
Since foobar=fubar="fucked up beyond all recognition", why would I want to install a Microsoft product on my nice Linux machine? That would be like putting a Yugo hood ornament on my Cadillac!
Installing a program named foobar would scare the hell out of me regardless of the installation method.
-mcgrew
mcgrew's razor: Never attribute to stupidity that which can be explained by greedy self-interest
You wouldn't need to worry about weather because you'd have the laser link on a satellite. The satellite would have a gyroscopically mounted laser, and would communicate with the remote station via radio and they would auto-align their lasers accordingly. Once a link was achieved, it should be fairly easy to keep it established, and the satellite would simply relay the info back to terra firma.
"Who would have thought that light could travel such a long distance?"
Who would have though the Canary Islands are that big?
-Charlie
Why not use GRB's, I heard they are pretty focused too and can "transmit" as far as 12.3 billion light years.
...
My guess is that generation and modulation can prove challenging, but once we set our minds nothing is impossible
So now they've invented tightbeam communications?
Wouldn't that just be a standard vanilla radio transmitter? If you're putting out a signal of constant frequency and phase, it's coherent. Agree?
OWNED!
Gravity Waves are theorized to propogate at the speed of light. If not, cause and effect can be violated.
Over-the-top Response Guy! Giving "Over-the-Top Responses" since 1970.
Careful what you wish for!
Things are not always what they appear to be.
In the vacume of space, you would not have to deal with light scattering either. However, I do see a problem with this. This looks like it would be great with, say, a moonbase, which is going to stay stationary on the surface of the moon. However, I do not see a real practical use for planetary spacecraft that are constantly in motion. With a laser communication system over that distance, you would have to have amazing pointing accuracy between the sender and reciever. If its off by even a hair, the laserbeam is going to miss the reciever by hundreds, if not thousands, of miles. With radio, you can at least point your high gain antennas "toward Earth", and anyone with an antenna on the ground pointing in that general direction at that frequency could pick up the signal. With laser, if you are pointing toward a satelite, you are no longer pointing at a huge circular object 24,000 miles in diameter, you are pointing at a satellite roughly 50 feet across to a reciever on that satelite that is roughly a few inches. IF, by some miracle, you were able to line it up, the spacecraft will have moved before you can even get verification of a successful link. So, no highdef realtime video from a planetary flyby.
However, and it would be tricky, and probably longer distances then they are planning on, but if you put a satelite in Earth orbit, and one in Mars orbit, and have them stationary (not geosynchronous, I guess stationary is the word I am looking for), then you might be able to establish a long term laser communication between the two. You could then have your landers on Mars uplink with the Mars orbiter when they come into view using satellite communications. This would lead to higher date rates to Martian ground vehicles, meaning less time needed to send and verify commands, and we no longer have to wait several minutes to get a high res picture, as it could probably send us high res video (with a strong enough antenna on the ground).
My question is, is this really a new concept? I am pretty sure I have read about similar technologies in Sci-Fi novels. This may be just the first time that they actually tried it.
streaming
Welcome to the Panopticon. Used to be a prison, now it's your home.
Well, high bandwidth maybe once the link is up, but the speed of light is still the same, so the delay doesn't change.
Excuse me, but please get off my Pennisetum Clandestinum, eh!
Inverse square law applies for isotropic (all directions) as well as directional sources (focused beam). The way the difference is handled is by introducing an antenna gain term, where the gain at a given point in space is defined to be the ratio of the power density due to the directional source to the power density of an isotropic source. In communications applications, you use Friis' Transmission Formula to compute received signal-to-noise ratio which includes a factor Pt*Gt/(4*pi*R^2), which is the power density at a receiving antenna (lense) a distance R from the transmitter, where Pt is the Power Transmitted and Gt is the gain of the transmitting antenna (lense). For a laser it is easy to get a high Gt (very directive) with a small lense because the wavelength is so small, but that still does not get one around the R^2 relationship.
Wow, and what a stunning refutation it is.
Has it occurred to you that the Voyager probe which was launched some 30 years ago may not be able to do that? Or that the protocol they used to ensure no data loss as the bits travel for several million or more miles would preclude streaming? Cause, really, if you're streaming out of a circular buffer, and the recipient says "what?", you have lost your data. When you're sending something into space as far as Voyager, you really can't afford any data loss. You have to treat every piece of data as if it's the most valuable data you're ever going to see -- cause it might be.
I'm sure the specific issues of getting data from Voyager which is old, very far away, built with minimal data storage, and too late to modify are slightly more complicated than your over-simplified solution of just streaming data.
It only does what it does now, and it's too late to change that. Just because it works for Real Player, sports feeds, and pr0n, doesn't make it practical for something which is at the edge of our solar system.
Cheers
Lost at C:>. Found at C.
http://www.space.com/missionlaunches/060104_laser_comm.html
The idea of streaming data is a fundamental construct in digital communications--and analog to digital converters (and conversely, digital to analog converters). Voyager had plenty of this type of technology, since all of its instruments were analog in design, and the outputs had to be converted to digital for processing, storage, digital to analog conversion, and finally transmittal back to hearth--i.e. a buffer, another significant idea in digital communications and processing technology. Furthermore, if we multiply by the rate these actions happen at, we get data rate.
If you can't get past this very, very basic idea, there is no hope for you here. In which case, please destroy your geek card and immediately exit the internets.
"Exactly like in space", except for the medium being (mostly) vacuum, extreme distance of gravity fields like that right next to the Earth, or interaction with all the other stuff, some unpredictable, along the vast interstellar distnaces.
"In theory, there's no difference between theory and practice. In practice, there is." - Yogi Berra
--
make install -not war
NASA already did this during the APOLLO days by bouncing a laser of the moon.
The earth-to-moon distance is 385K Km which round trip would be 770K Km.
Thus 770K times 2 is 1,540KM or 1.54 million Km which is two round trips to the moon.
The only thing they didn't do is transmit data as far as I know.
As for the article they did it all in the earths atomosphere vs. NASA which was part
atmosphere and part space.
1.5 million Kilometers is not very far, even in terms of the solar system. It's about 0.01 Astronomical units, or about 1% of the distance from Earth to the Sun, or 2.6% of the distance to Mars (at closest approach).
You'd need a much more powerful laser, or a more sensitive detector, to communicate over inteplanetary distances.
Unless it works in miles, the US will never be able to use it. We don't fathom kilometers here.
Now lets assume that we've got a 10 W green laser with a 10cm primary mirror on the transmitter with 1.40 arcsecond resolution.
At 24 billion km distance that turns out to be a flux of 330 photons per second per square meter. Lets assume that our detectors have low background (i.e. we're photon limited) and that we want a bit error rate of 1e-6 and a detection threshold of 3 photons, so we'll require an average of 15 photons per bit, and for simplicity sake we'll assume we're using a compact encoding. We'll want, at the minimum, to replicate that 1.4 kbps that the radio transmitter gets.
So we need to receive 21000 photons/second, which corresponds to a telescope area of 64 m^2 or, equivalently a 9 meter effective diameter primary. Keck would do nicely, but might be a bit more expensive than the Goldstone antenna. If you want to do twice the bit rate of the radio tranmitter, you'll need both Keck telescopes or a 13 meter telescope.
In other words, lasers aren't quite the panacea for interplanetary communications that they might seem to be at first. You can increase bandwidth by increasing the size of the receiving telescope, but you can do that with radio, too. It just cost money. You usually don't have the option of increasing the size or power of the sending side in either case. For radio, big dish antennas are heavy. For optical, sub-arcsecond pointing systems are heavy and expensive.
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Never...no, no, ALWAYS, check your references...
What would you use a laser that big for?
I dunno, making enormous swiss cheese?
Didn't anyone ever tell you to make sure your optics were clean?
Here, try this
what is it?
I dunno, i found it in one of the labs....
This would work really well in environments that are pretty clear. I only studied a little astronomy but, what if we were to:
- Use radio from the ground to orbit? I think this is pretty common already. Lasers as we know suffer more from weather than radio.
- Use laser from Earth orbit to furthest possible point without a significant signal loss.
- And then, use radio from that point on?
Imagine you're trying to send a signal from a clear area, through a forest, to another clear area. Laser wouldn't work through the forest, but radio would.
I also think that laser would require more power than radio, making it more feasible to have laser power outside of Earth orbit, then using radio for further away.
What do you think?
I read a novel by David Gerrold called Jumping off the Planet. The author refers to inter stellar lasers being used as a long term way to store data as the lasers just continue to transmit the stuff around indefinitely. Interesting, not sure of the practicality though.
You don't hear about 80 million kilobyte hard drives. Why not gigameters instead of million kilometers? Well, perhaps that'd start the confusion between powers of 2 and 10-- is 1 megameter 1024 kilometers or 1000 kilometers?
Intellectual Property is a monopolistic, selfish, and defective concept. It is "tyranny over the mind of man"
... across a distance of 1.5 million kilometers ...
Huh? That's 5 light seconds. That barely gets you past the moon. It doesn't get you anywhere near another planet, much less out into the "universe".
Let's hold off talking about "huge distances" when we're dealing with at least a few thousand light years. (Even then, that doesn't get you outside the galaxy.)
Those who do study history are doomed to stand helplessly by while everyone else repeats it.
JPL's been working on it too for a while now... and with similar datarates, and a ground acquisition plan to boot.
http://lasers.jpl.nasa.gov/PAGES/pubs.html#ocd
But, yes, a laser link indeed is desirable. Sure, we can still contact Voyager with radio telescopes, but even from the Mars rovers, notice how it takes so long to get from Mars to grainy B&W picture back on Earth?
Sending back live video feeds and more full colour images sets the data rate bar much, much higher. Getting this much data back quickly is limited by the frequency of the radio waves/light. Laser light has an over 1,000 times shorter wavelength than Ka band radio telescopes can manage (that's what NASA uses now to talk to the Mars probes), which increases the potential amount of data that can be sent in a given timeframe by essentially that amount.
In addition, because laser light is focused so narrowly, it wastes much less energy than a radio antenna which must spray a good portion of space with radio waves in order to hit Earth. Imagine focusing your mag-light in the dark... the narrower the focus, the brighter the beam gets, because more energy is packed into less space. The challenge though, is that you have to aim much more precisely at Earth to compensate for that more focused beam.
Here's a great overview of JPL's long-term vision:
http://lasers.jpl.nasa.gov/PAPERS/REVIEW/overview.pdf
As a good nerd, one of the books I love most in my library is David G. Aviv's Laser Space Communications (2006). It is really one of the best introductory books for any laser or communications nerd. I actually do some personal research in the area as I know very well that in the future laser space communications will become a multi-billion industry, thanks to the greater presence of humans in space. Considering the 5-GENIN (fifth-generation Internet), I can predict that more Internet entrepreneurs will move into space when it becomes more mainstream. The laser space communications is an example of a technology which if you can make a contribution now or formulate a good idea you are likely to become rich easily and quickly (unless our space development gets delayed by a major war or catastrophe).
But consider the pigeon's unique capacity to recognize objects regardless of spatial orientation.
The common gray pigeon can easily distinguish among items displaying
only the minutest differences, an ability that enables
it to select relevant web sites from among thousands!
.
- aqk
F U
What we really need is a laser that travels a few feet, and makes a swishing noise when you wave it around.
Sarcasm is no substitute for thought.
Here's streaming, ca. 1950: take a sensor. Wire it to a radio transmitter. Operate the sensor and the transmitter.
Storage required? ZERO.
Kids these days. Everything's gotta be digital, buffered, and pr0n-compatible. Sheesh.
Welcome to the Panopticon. Used to be a prison, now it's your home.
If I recall, one of the requirements for the new Lunar X Prize is the shooting of some high-def video from the lunar surface. (For some *very* pricey stock footage!) I imagine it would be much easier to do that with a high-capacity link, such as what you'd get with a laser. This is the sort of technology that the X Prize (and NASA) should be supporting.
What, pray tell, is a "conventional radio link"? Actually, don't bother. There is no such thing. Radios merely broadcast without knowing anything about who is receiving the signal.