Longest Laser Link Set for Moon Launch

Longest LaserLast March, a laser-ranging system on the United States’ East Coast beamed a tiny image of the Mona Lisa to NASA’s Lunar Reconnaissance Orbiter. The transmission, which reached the spacecraft while it was in orbit around the moon, was just a trickle of data by Earth standards, topping out at 300 bits per second.

There’s a new laser-based system being tested right now that could detect turbulence in a plane’s path long before the first drink hits the floor.

Soon, that modest demonstration could be trumped by a much faster, two-way link. On 6 September, the Lunar Laser Communication Demonstration (LLCD) is set to launch to the moon. Once in orbit, it is expected to be able to receive data from Earth via laser at a rate of 20 megabits per second and send data back at up to 620 Mb/s. If all goes well, researchers say, the experiment could someday enable spacecraft to send high-definition video from other planets and allow high-bandwidth communication with astronauts who venture beyond the moon.

Over the years, a number of Earth-orbiters have tested laser links with the ground and between spacecraft, and a few proof-of-principle laser pings have been sent to a spacecraft en route to Jupiter and exchanged with another headed to Mercury. But LLCD, which will orbit a good 10 times as far from Earth as geosynchronous satellites, “will be the longest laser communications link ever attempted,” says Don Boroson, who led the design team for the instrument at MIT’s Lincoln Laboratory. LLCD will attempt to receive data using an onboard 10-centimeter telescope and transmit it back with a half-watt laser.

source : http://news.discovery.com/space/longest-laser-link-set-for-moon-launch-130820.htm

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