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Fri September 6, 2013
Communications Gear Hitches Ride With Lunar Probe
Originally published on Fri September 6, 2013 11:40 am
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It's MORNING EDITION from NPR News. Good morning, I'm Steve Inskeep.
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And I'm Renee Montagne. Tonight, a rocket will blast off from a launch pad in Virginia carrying a spacecraft headed for the Moon. NASA's Lunar Atmosphere and Dust Environment Explorer will, yes, study the lunar atmosphere and dust environment. But what really intrigued NPR's Joe Palca is a package of communication gear that's hitching a ride with the lunar probe. If it works, it would be or could be the start of a revolution in laser-based communication in space and on Earth.
And here's Joe Palca with the report.
JOE PALCA, BYLINE: Today, if you want to talk to someone on the Moon, assuming there was someone there to talk to, you're pretty much stuck with radio waves. But that could be changing.
DON CORNWELL: I'm Don Cornwell. I'm the mission manager for the Lunar Laser Communications Demonstration. It's something we've been working on for the last five years.
PALCA: Cornwell says using light waves instead of radio waves to communicate has several advantages. One is you don't need a big antenna on your spacecraft.
CORNWELL: Instead, we have this four inch telescope here, that's mounted on a gimbal, and this is our antenna now.
PALCA: Another is laser light doesn't spread out as much over long distances.
CORNWELL: A radio beam from the Moon, it spreads out and it would cover the Western United States. And our beam is about six kilometers in diameter, or about four miles - so it's much, much smaller.
PALCA: A smaller beam means you lose less energy as the beam travels to Earth, so you need less power to send your laser signal.
CORNWELL: We're going to do it with half weight and with 25 percent less power than a comparable radio frequency communications system.
PALCA: Another advantage of lasers is you can pack a lot of digital data in your signal. Cornwell says the package NASA is sending to the Moon will transmit data at 622 megabits per second, way faster than any other deep space communication system.
Don Boroson is part of the team at MIT Lincoln Laboratory that built the test package. He says one of the toughest things about laser communications is finding the exact spot where the laser is coming from, because for the system to work the sender and receiver must be pointed directly at each other.
DON BOROSON: Much of the technology is how do you find where that spot was in the first place, and then when I see it how do I hold it still and not have it jiggle around too much.
PALCA: The good news is that even from the Moon, and even during the day, a telescope on Earth can spot the lunar orbiter's laser.
BOROSON: We're so bright from that little dot in the sky that the background hardly makes any difference.
PALCA: Using lasers to communicate is not a new idea. It's been around for some three decades down here on Earth.
MIKE PERISCO: It started off like many projects as a Department of Defense initiative.
PALCA: Mike Persico is CEO and founder of Anova Technologies, a company that operates laser communications systems. He says the military's interest in this technology is because it can transmit huge amounts of data, and it's almost impossible to intercept. And as long as the sender can see the receiver, it's much faster to send laser signals directly than to send them over fiber optic cables, the way it is done now.
That high speed, point-to-point communications is something brokerage firms have taken advantage of. Trading stock a split second faster than your competitor can translate into huge profits.
PERISCO: Five milliseconds in the world of computerized trading is like three weeks to you and I. That's an advantage you could drive a Mack truck through.
PALCA: Persico predicts many other industries will adopt laser communication systems. He says just about any industry that needs large amounts of data moved quickly from one point to another could benefit from a direct laser system. And with laser communications, your friends on the Moon will have the bandwidth to send you live HD video from the famous lunar landmarks they visit.
Joe Palca, NPR News. Transcript provided by NPR, Copyright NPR.