Recently NASA released result of its LLCD (Lunar Laser Communication Demonstration) as a 30-days test was carried out by its Lunar Atmosphere and Dust Environment Explorer (LADEE) which is still in orbit around the moon. In this result LLDC claimed that laser communication are practical at a distance of quarter of million miles and this system could perform as well although not better than NASA radio system.
The LLDC means process of practically using broadband lasers for deep space communication with download speeds orders of magnitude greater than conventional radio communication. LLDC transmitted a record breaking download on October 20 from lunar orbit using a pulsed laser beam that was picked up by the main LLCD ground station in New Mexico, which is one of three set up in the US and Spain. LLCD has capability to transmit data to Earth at 622 megabits per second and upload at 20 Mbps.
NASA further explained that LLCD performed better than expected during its recent 30-days trial. During the trial the laser was able to communicate with Earth stations in broad daylight even when the Moon had less than 4 degrees of separation from the Sun. It performed with zero error when the Moon was low on the horizon, stressing the laser to pass through a much thicker layer of atmosphere. It is surprising that light clouds were not an obstacle on the way during transmission.
“We were able to program LADEE to awaken the LLCD space terminal and have it automatically point and communicate to the ground station at a specific time without radio commands,” says Don Cornwell, LLCD mission manager at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “This demonstrates that this technology could serve as the primary communications system for future NASA missions.”
NASA claimed that trial was not only successful but the LLCD transmit the entire data library of LADEE spacecraft at paralleled speed by sending a GB of information on Earth in under 5 minutes. Normally, such a download takes several days. NASA disclosed that with the completion of LLCD, the next phase is LRCD (Laser Communications Relay Demonstration) satellite set to be launched in 2017 with latest laser system having capability of handling up to 2.880 Gbps from geosynchronous orbit a part of 5-years demonstration.
