ABSTRACT
Laser communication and ranging experiments were successfully conducted from the satellite laser ranging (SLR) station at NASA Goddard Space Flight Center (GSFC) to the Lunar Reconnaissance Orbiter (LRO) in lunar orbit. The experiments used 4096-ary pulse position modulation (PPM) for the laser pulses during one-way LRO Laser Ranging (LR) operations. Reed-Solomon forward error correction codes were used to correct the PPM symbol errors due to atmosphere turbulence and pointing jitter. The signal fading was measured and the results were compared to the model.
Subject(s)
Information Storage and Retrieval/methods , Lasers , Models, Theoretical , Signal Processing, Computer-Assisted/instrumentation , Spacecraft/instrumentation , Telecommunications/instrumentation , Computer Simulation , Equipment Design , Equipment Failure AnalysisABSTRACT
Here we report timed observations with subnanosecond precision of short laser pulses at a distance of nearly 24 million kilometers between the Mercury Laser Altimeter (MLA) aboard the MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) spacecraft and the NASA Goddard Geophysical and Astronomical Observatory (GGAO). Forty MLA downlink observations and 90 uplink observations were obtained during observing sessions on 27 and 31 May 2005. Precise standard ground timing allowed a solution for spacecraft range, range rate, and acceleration, as well as clock bias. This experiment established a new distance record for laser detection and accomplished a two-way laser link at an interplanetary distance.
