http://www.digitaljournal.com/science/enjoy-high-speed-internet-on-the-moon/article/384579

Enjoy high-speed Internet on the moon

Posted May 24, 2014 by Sonia D'Costa
Although wireless Internet is still not available at several places over the globe, a team of NASA and MIT research scientists have shown that it can be made available on the moon.
Wireless broadband can be made available on moon.
Wireless broadband can be made available on moon.
Photo from Wikimedia.org
To make high-speed Internet available on the moon, uplink signals are first sent to it from four telescopes based on a ground terminal. Information in the form of invisible infrared light pulse codes is fed into each telescope through a laser transmitter, resulting in transmitter power of 40 watts.
Each of the four telescopes used to send uplink signals to the moon transmit light pulse codes through different air columns, owing to which the chances of at least one of them reaching the receiver are multiplied. The receiver is located on a satellite that currently goes around the moon, and the satellite has a telescope that receives the laser beams and turns them onto optical fibers. A photo-detector then converts the light pulses into electrical pulses that are finally turned into data.
The technology has already been used to transmit data between the moon and the Earth, which are separated by a distance of 384,633kms, at a speed of 19.44mbps and to download data at a speed of 622mbps.
Mark Stevens, an MIT research scientist, says: “Communicating at high data rates from Earth to the moon with laser beams is challenging because of the 400,000-kilometer distance spreading out the light beam. It’s doubly difficult going through the atmosphere, because turbulence can bend light-causing rapid fading or dropouts of the signals at the receiver.”
The research team will present its study at the CLEO Laser Technology Conference, which is scheduled to be held at California on June 9, 2014. Currently, the findings can be viewed at the Optical Society website. At the conference, the team will show how their laser-powered uplinks between the Earth and its satellite can beat the highest transmission speeds achieved on earth so far.