New MIT technology could provide fast and reliable extra-terrestrial broadband connections.
Space travel might just have got a little more entertaining, as any future colonists living on the Moon may be able to enjoy all the benefits of online access that their Earth-bound compatriots do, thanks to a new breakthrough by American researchers.
Working with NASA, a team from the Massachusetts Institute of Technology (MIT) Lincoln Laboratory has for the first time demonstrated that data communication technology that can provide those outside of our planet with the broadband connectivity currently in place on Earth.
The connection is stable enough to enable large data transfers and even provide high-definition video streaming, meaning astronauts would be able to communicate with friends or colleagues back on earth via video chat.
Alternatively, it could allow Moon dwellers to catch up on their favourite television shows, the researchers suggested.
The team will present their technology for the first time at the CLEO:2014 conference next month in San Jose, giving an overview of the on-orbit performance of their laser-based communication uplink between the moon and Earth, which beat the previous record transmission speed last fall by a factor of 4,800.
"This will be the first time that we present both the implementation overview and how well it actually worked," Mark Stevens of MIT Lincoln Laboratory said of the technology. "The on-orbit performance was excellent and close to what we’d predicted, giving us confidence that we have a good understanding of the underlying physics".
The team made history last year when their Lunar Laser Communication Demonstration (LLCD) transmitted data over the 384,633 kilometres between the moon and Earth at a download rate of 622 megabits per second, faster than any radio frequency (RF) system.
They also transmitted data from the Earth to the moon at 19.44 megabits per second, a factor of 4,800 times faster than the best RF uplink ever used.
"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," Stevens says. "It’s doubly difficult going through the atmosphere, because turbulence can bend light — causing rapid fading or dropouts of the signal at the receiver."
In order to overcome the issue of the signal fading over such a long distance, the team’s technology combines a number of techniques, using four separate telescopes to send the uplink signal.
Each of these transmits light through a different column of air that experiences different bending effects from the atmosphere, Stevens said, increasing the chance that at least one of the laser beams will interact with the receiver, which is mounted on a satellite orbiting the moon.
This receiver uses another telescope to collect the light, which is then amplified and converted into data bit patterns which transmit the message.
Of the 40 watt signals sent by the transmitter on the ground, less than a billionth of a watt is received at the satellite — but this is still 10 times the signal strength necessary to achieve error-free communication according to Stevens.