33
edits
Changes
Jump to navigation
Jump to search
Line 4:
Line 4: − − === Mission Success and Demonstrations ===+ − The LLCD experiment is regarded as a great success. All systems operated at or above expected levels, and it was demonstrated that an optical link could be established without human-in-the-loop interaction. Line 14:
Line 12: − + − + +
The Field of Optical Communications (view source)
Revision as of 19:59, 22 March 2016
, 19:59, 22 March 2016→MIT Lincoln Labs LLCD/LADEE
== MIT Lincoln Labs LLCD/LADEE ==
== MIT Lincoln Labs LLCD/LADEE ==
Nasa's Lunar Laser Communication Demonstration (LLCD) was a rousing success that demonstrated duplex laser communications at previously unheard-of speeds between lunar orbit and ground stations on Earth (These download speeds were at times faster than the ground lines on Earth when distributing downloaded scientific data). The LLCD's space component was attached as an optical payload to the larger scientific satellite LADEE.
Nasa's Lunar Laser Communication Demonstration (LLCD) was a rousing success that demonstrated duplex laser communications at previously unheard-of speeds between lunar orbit and ground stations on Earth (These download speeds were at times faster than the ground lines on Earth when distributing downloaded scientific data). The LLCD's space component was attached as an optical payload to the larger scientific satellite LADEE.
The LLCD project operated on the 1.5-micron band with maximum downlink speeds of 622Mbs. The project featured a 1kHz squarewave acquisition signal and could measure its round-trip Time of Flight (TOF) to within 200 psec.
The LLCD project operated on the 1.5-micron band with maximum downlink speeds of 622Mbs. The project featured a 1kHz squarewave acquisition signal and could measure its round-trip Time of Flight (TOF) to within 200 psec.
All systems operated at or above expected levels, and it was demonstrated that an optical link could be established without human-in-the-loop interaction. Several demonstrations of the system were executed, and are described below.
==== High Speed Telemetry ====
==== High Speed Telemetry ====
==== High Volume Download ====
==== High Volume Download ====
During one experiment, test data from another LADEE experiment was transmitted via the optical link. The 1GB of data was transmitted in under five minutes (error -free). The same amount of data would have consumed every RF window for three days to transmit.
During one experiment, test data from another LADEE experiment was transmitted via the optical link. The 1GB of data was transmitted in under five minutes (error-free). The same amount of data would have consumed every RF window for three days to transmit.
The information was then relayed to scientist on the ground using existing infrastructure that was often slower than the optical link itself. This process was executed several times at the request of LADEE scientists and gave them an unprecedented amount of data to process.
The information was then relayed to scientist on the ground using existing infrastructure that was often slower than the optical link itself. This process was executed several times at the request of LADEE scientists and gave them an unprecedented amount of data to process.
==== Webcam Livestream ====
==== Webcam Livestream ====
An HD webcam was setup in the operations center and broadcast its information up and around the moon before coming back. Viewers would see their movements about seven seconds delayed on the big screen. "Needless to say, this was a very popular feature of the demonstration."
==== Ground Station Handover ====
==== Ground Station Handover ====
==== Open-Loop Optical Lock On ====