Images Of The Mona Lisa On The Moon
Now all the galaxy can see the Mona Lisa smile.
NASA has taken Leonardo da Vinci's
masterpiece and turned it into the first digital image to be transmitted
by laser beam from the Earth to an orbiting spacecraft approximately
240,000 miles away. The
process uses a laser-tracking system from NASA's Lunar Reconnaissance
Orbiter, which has been circling the moon for three-and-a-half years.
Pixels: The famous face was broken down into thousands of tiny bits for easier transmission
Laser pulses are sent from the Next Generation Satellite Ranging station
at Goddard Space Flight Center in Maryland to the probe to mark its
location in lunar orbit. To send the Mona Lisa into space, researchers encoded a
black-and-white version of the portrait which was in turn made into a
series of values in a 152-by-200-pixel grid. Each value represented a shade from black to gray to white, measured from zero to 4,095.
The signal for each pixel was sent on the ranging station's
laser-tracking pulse, with each pulse fired during one of 4,096
designated time slots at a rate of 300 bits per second. The probe's Lunar Orbiter Laser Altimeter then used the timing of the pulses to determine the grayscale value of each pixel.
The process had a 15 per cent error rate.
Once broken down the Mona Lisa's image was broadcast more than 240,000 miles into space via laser
Finally the picture was processed and transmitted back to earth via the orbiter's standard radio communication system. The experiment's principle author,
Goddard's Xiaoli Sun, said the painting was chosen because it was far
more visual than other subjects, and its something people would
recognize easily. 'It's a
familiar image with lots of subtlety,' he told NBC News. 'You can immediately
feel whether the image looks right, and how much information got lost.'
'In
the near future, this type of simple laser communication might serve as
a backup for the radio communication that satellites use,' said David
Smith, of the Massachusetts Institute of Technology. 'In the more
distant future, it may allow communication at higher data rates than
present radio links can provide.'
NASA plans to use a higher-bandwidth
laser communication for its next moon mission, called the Lunar
Atmosphere and Dust Environment Explorer. When launched in August, it will carry an experimental laser that can transmit data at more than 600 million bits per second.
NASA
is scheduled to launch the Laser Communications Radar Demonstration
into orbit aboard a commercial satellite in 2017. That experiment a
full, beam-based communication system.
Laser systems could potentially transmit data 10 to 100 times faster than radio systems with the same mass and power.
