This is pretty cool. NASA has figured out how to piggy-back non-native data on top of laser telemetry signals sent to the Lunar Reconnaissance Orbiter and decode it.
As part of the first demonstration of laser communication with a satellite at the moon, scientists with NASA’s Lunar Reconnaissance Orbiter (LRO) beamed an image of the Mona Lisa to the spacecraft from Earth.
The iconic image traveled nearly 240,000 miles in digital form from the Next Generation Satellite Laser Ranging (NGSLR) station at NASA’s Goddard Space Flight Center in Greenbelt, Md., to the Lunar Orbiter Laser Altimeter (LOLA) instrument on the spacecraft. By transmitting the image piggyback on laser pulses that are routinely sent to track LOLA’s position, the team achieved simultaneous laser communication and tracking.
“This is the first time anyone has achieved one-way laser communication at planetary distances,” says LOLA’s principal investigator, David Smith of the Massachusetts Institute of Technology. “In the near future, this type of simple laser communication might serve as a backup for the radio communication that satellites use. In the more distant future, it may allow communication at higher data rates than present radio links can provide.”
Typically, satellites that go beyond Earth orbit use radio waves for tracking and communication. LRO is the only satellite in orbit around a body other than Earth to be tracked by laser as well.
Check the article at the NASA LRO page for more info on how they did it.