Good Day World!
Those jokers at NASA sure come up with some interesting experiments. Your going to have to read the following story to find out why they used the Mona Lisa as their groundbreaking transmission.
The Mona Lisa’s enigmatic smile has become the first digital image to be transmitted via laser beam from Earth to a spacecraft in lunar orbit. I guess the scientists wanted any onlookers to know that we’re a classy race with a sense of wry humor.
Check out why we should be impressed with this breakthrough:
(The composite image on the right shows how the Mona Lisa image looked after its trip to the moon. The left side shows the picture before error correction, and the right side shows how it looked after error correction.)
“NASA has turned the Mona Lisa into the first digital image to be transmitted via laser beam from Earth to a spacecraft in lunar orbit, nearly 240,000 miles away, thanks to a technology that may soon become routine.
The experiment took advantage of the laser-tracking system that's in operation aboard NASA's Lunar Reconnaissance Orbiter, which has been circling the moon for the past three and a half years. NASA sends regular laser pulses from the Next Generation Satellite Ranging station at Goddard Space Flight Center in Maryland to the space probe's Lunar Orbiter Laser Altimeter, or LOLA, to measure its precise position in lunar orbit.
For last March's Mona Lisa maneuver, researchers encoded a black-and-white version of Leonardo da Vinci's enigmatic masterpiece as a series of values in a 152-by-200-pixel grid. Each value represented a shade of black to gray to white, ranging from zero to 4,095. The signal for each pixel was then piggybacked on the ranging station's laser-tracking pulses: Each pulse was fired during one of 4,096 super-short designated time slots, at a rate of about 300 bits per second.
As the pulses were received in lunar orbit, LOLA's software used the precise timing of each pulse to figure out the grayscale value for a given pixel — and reassembled the black-and-white image. The process wasn't perfect: Atmospheric turbulence introduced laser transmission errors, even when the sky was clear. To accommodate the 15 percent error rate, the researchers used Reed-Solomon data coding, which is the same method used to smooth out the bumps in the playback of CDs and DVDs.
The picture was reprocessed and sent back to Earth using the orbiter's standard radio communication system, just to make sure that Mona survived the trip intact. Throughout the experiment, Lunar Reconnaissance Orbiter conducted its regular mapping tasks without interruption.
A research report on the experiment, with Goddard's Xiaoli Sun as principal author, was published online by Optics Express on Thursday. (Read the rest here)
Time for me to walk on down the road…
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