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NASA's LLCD tests confirm laser communication capabilities in space

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December 26, 2013

Artist's concept of the LLCD transmitting to Earth (Image: NASA)

Artist's concept of the LLCD transmitting to Earth (Image: NASA)

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This week, NASA released the results of its Lunar Laser Communication Demonstration’s (LLCD) 30-day test carried out by its Lunar Atmosphere and Dust Environment Explorer (LADEE) that is currently in orbit around the Moon. According to the space agency, the LLCD mission proved that laser communications are practical at a distance of a quarter of a million miles and that such a system could perform as well, if not better, than any NASA radio system.

The LLCD is a demonstration of the practicality of using broadband lasers for deep space communications with download speeds orders of magnitude greater than conventional radio communications. With the ability to download data to Earth at 622 megabits per second (Mbps) and upload at 20 Mbps, the LLCD transmitted a record-breaking download on October 20 from lunar orbit using a pulsed laser beam that was picked up by the main LLCD ground station in New Mexico, which is one of three set up in the US and Spain.

Lasers have inherent advantages over radio, not the least of which is that they have a much greater bandwidth capacity and their ability to produce a narrow, coherent beam means that they use less power over longer distances – a prime concern for spacecraft that often have to make do with power levels usually associated with incandescent bulbs.

NASA says that the LLCD mission performed better than expected during its 30-day trial. The laser was able to communicate with the Earth stations in broad daylight and even when the Moon had less than four degrees of separation from the Sun. It also worked without error when the Moon was low on the horizon, forcing the laser to pass through a much thicker layer of atmosphere, with atmospheric turbulence having little effect. The space agency was even surprised that light clouds weren’t an obstacle.

Artist's concept of LADEE entering lunar orbit (Image: NASA)

In addition to this lack of error, the LLCD was able to switch from one ground station to the next as the Earth turned in a manner that NASA compared to how a mobile phone network operates, and the system did so without human intervention. The system could even lock on to the ground stations without using a radio signal.

"We were able to program LADEE to awaken the LLCD space terminal and have it automatically point and communicate to the ground station at a specific time without radio commands," says Don Cornwell, LLCD mission manager at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "This demonstrates that this technology could serve as the primary communications system for future NASA missions."

NASA says that not only was the test successful, but that the LLCD was able to download the LADEE spacecraft’s entire library of data at unprecedented speeds, sending a gigabyte of information to Earth in under five minutes at a speed that was largely limited by LADEE’s ability to hand the data off to the LLCD. Normally, such a download would take several days.

NASA says that with the LLCD mission complete, the next phase will be the Laser Communications Relay Demonstration (LRCD) satellite set to launch in 2017 with a more advanced laser system capable of handling up to 2.880 Gbps from geosynchronous orbit as part of a five-year demonstration.

The video below is a high-definition transmission of congratulations from NASA Administrator Charles Bolden, which was transmitted to the Moon and back using the laser system.

Source: NASA

About the Author
David Szondy David Szondy is a freelance writer based in Monroe, Washington. An award-winning playwright, he has contributed to Charged and iQ magazine and is the author of the website Tales of Future Past.   All articles by David Szondy
9 Comments

Now, how about using this for "cheap fast internet that is not linked to some fat-cat-telecoms company" in rural arias on mars... sounds like it might even have a slight chance of working on earth too...but I guess I shouldn't push my luck like that...

Michiel Mitchell
27th December, 2013 @ 04:01 am PST

Add this to ISS & bring this to Earth for Internet Use

Offer

DSL

Cable

Fiber Optics

& LaserNet.

Awesome.

Stephen N Russell
27th December, 2013 @ 02:20 pm PST

Very impressive, especially the locking on capability, of course a quarter of a million miles is nothing on astronomical scales, but this is only the beginning I guess, because light can travel over many lightyears. but then takes its time, that is the problem. maybe there is still hope for the entangled photon idea, although the bandwidth of that seems insufficient.

jochair
27th December, 2013 @ 04:09 pm PST

Reality not only catches up to SciFi it surpasses it. "Whisker Lasers" have been frequently used in SciFi stories as a stealthy but low bandwidth means of communication between spaceships.

Now there's point to point, high bandwidth laser communication.

Gregg Eshelman
27th December, 2013 @ 08:40 pm PST

Saw this on robotec 20years ago lol and now on dvd

Leonard Foster Jr
27th December, 2013 @ 09:04 pm PST

For the past 20 years I've been wondering why we are looking for radio signals from other civilizations. We might just as well be looking for smoke signals. Any advanced civilization will start and end their radio communication in probably a century (or two at the most). Then move on to laser or something we haven't even considered.

Mike Kling
28th December, 2013 @ 07:29 am PST

@ Gregg Eshelman

Compared to much more powerful and multiple frequency "laser" systems the low power whisker laser system would have a low bandwidth.

Slowburn
28th December, 2013 @ 08:46 am PST

@Mike Kling:

Because, by your own analysis, their radio comms will get here first.

dalroth5
31st December, 2013 @ 01:31 am PST

How does the satellite aim the laser and lock on?

MrGadget
31st December, 2013 @ 08:25 am PST
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