What would you need to survive on the Moon? Air, water, some food, and if you ask the average American - wi-fi. We still have to wait for the air, water and food, but according to researchers from NASA and MIT, wi-fi on the Moon is quite feasible. They've even made a demonstration, downloading information from the moon at a rate of whopping 622 megabits per second.
In order to enable future astronauts to take lunar selfies, the two organizations used four separate telescopes based at a ground terminal in New Mexico to send the uplink signal to the moon; each of the telescopes measured about 6 inches in diameter and were fed by lasers. The laser transmitters send information as coded pulses of infrared light feeds into each of the telescopes, resulting in 40 watts of transmitting power. Wi-fi routers, on average, consume 2 to 6 watts; on average, just a billionth of a watt from the 40-watt reaches the target satellite, but that's more than what's needed to ensure reliable communications.
Previously, information was downloaded from the moon through radio waves, but this method surpasses previous transmission speeds by a factor of 4,800.
The team managed to transmit the data across the 384,633km beteween the Earth and the Moon at a top rate of 19.44mbps and has also managed to download data at a rate of 622mbps. Better than your average internet, most likely.
"Communicating at high data rates from Earth to the moon with laser beams is challenging because of the 400,000-kilometre distance spreading out the light beam," says Mark Stevens of MIT Lincoln Laboratory. "It's doubly difficult going through the atmosphere, because turbulence can bend light-causing rapid fading or dropouts of the signal at the receiver."
Interestingly enough, each of the 4 telescopes used to beam the connection to the moon transmits light through a different column of air, and therefore all of them experience different effects of reflection, refraction and diffraction. While this lowers the chance of all of them reaching the destination, it dramatically increases the chances of one of them reaching it - which is all that's needed, really. The destination here is not the Moon itself, but a satellite currently orbiting the moon, equipped with a telescope, which collects the laser beam(s) and focuses it/them into an optical fibre. Then, a photodetector turns the pulses of light into electrical pulses and from there they are converted to data through conventional techniques.
Via Wired.
