Researchers from the Massachusetts Institute of Technology’s (MIT) Lincoln Laboratory, working with NASA, demonstrated for the first time that a data communication technology exists that can provide space dwellers with the connectivity we all enjoy here on Earth, enabling large data transfers and even high-definition video streaming.
At the Conference on Lasers and Electro-Optics (CLEO), being held next month in California, US, the team will present new details and the first comprehensive overview of the on-orbit performance of their record-shattering laser-based communication uplink between the Moon and Earth, which beat the previous record transmission speed by a factor of 4,800.
Earlier reports have stated what the team accomplished, but have not provided the details of the implementation.
“This will be the first time that we present both the implementation overview and how well it actually worked,” said Mark Stevens of MIT Lincoln Laboratory.
“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,” Stevens said.
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 kilometre distance spreading out the light beam,” Stevens said.
“It’s doubly difficult going through the atmosphere, because turbulence can bend light-causing rapid fading or dropouts of the signal at the receiver,” said Stevens.
To outmanoeuvre problems with fading of the signal over such a distance, the demonstration uses several techniques to achieve error-free performance over a wide range of optically challenging atmospheric conditions in both darkness and bright sunlight.
A ground terminal at White Sands, New Mexico, uses four separate telescopes to send the uplink signal to the Moon.
Each telescope is about 6 inches in diameter and fed by a laser transmitter that sends information coded as pulses of invisible infrared light.