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  • [piano music, LRO title]

  • [piano music, LRO title] Narrator: NASA scientists routinely use lasers to track the

  • position of the Lunar Reconnaissance Orbiter's laser altimeter as it orbits the moon.

  • Recently, however, they also tried something a little...different. In addition to tracking

  • the instrument, they used the laser to send a picture of the famous Mona Lisa in the first demonstration

  • of laser communication with a satellite at the moon. To do this, the LRO team

  • used the existing laser tracking signal--sent by the Next Generation Satellite Laser

  • Ranging Station at NASA's Goddard Space Flight Center. The image was divided into pixels,

  • which were then sent to the spacecraft one at a time by re-timing the regular tracking pulses.

  • By delaying the tracking pulses by specific amounts, LRO scientists

  • could use the difference between the expected arrival time and the actual arrival time to indicate the brightness

  • of an individual pixel. Once the image was sent, scientists corrected for

  • transmission errors caused by the Earth's atmosphere using common techniques used in CDs and

  • DVDs. They also studied signal fluctuations due to Earth's atmosphere.

  • The final image was verified when it was returned to Earth using LRO's radio telemetry system.

  • This test--and the data obtained from it--sets the stage for future

  • high data-rate laser communication demonstrations that will be a central feature of NASA's next

  • moon mission, the Lunar Atmosphere and Dust Environment Explorer. So, while

  • lasers are currently being used to track NASA satellites, in the future they may also be used to communicate

  • with them, sending not only data, but perhaps images that one day wil be as famous as...

  • the Mona Lisa. [piano music, Mona Lisa image]

  • [piano music, beeping, satellite flies by Earth]

  • [piano music, beeping, Goddard Space Flight Center information]

  • [piano music]

  • [piano music fades, black screen]

[piano music, LRO title]

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