On Tuesday, the laser transceiver on the Psyche probe sent and received data using laser beams from beyond the Moon for the first time.
NASA’s Space Optical Communications (DSOC) experiment transmitted near-infrared laser-encoded data from a distance of about 10 million miles to the Hale Telescope at Caltech’s Palomar Observatory.
Optical communications have already been used to transmit data from Earth and Moon orbit, but the latest test set a record for the range of laser beams as NASA seeks to improve its communications capabilities ahead of upcoming missions into deep space.
Reaching first gear is a huge success. Ground systems successfully detected deep space laser photons from the DSOC transmitter on board Psyche, and we were also able to send some data, meaning we were able to exchange ‘bits of light’ back and forth between space.
— Abi Biswas, DSOC project technologist at NASA’s Jet Propulsion Laboratory (JPL)
The DSOC transceiver was launched aboard the Psyche spacecraft on October 13 as the first demonstration of laser or optical communications from places as far away as Mars. The primary goal of the Psyche spacecraft is to explore and study the unique metallic asteroid Psyche to better understand planet formation and core dynamics. Laser communication systems package data into vibrations of light waves in lasers, encoding the message into an optical signal that is transmitted to the receiver via infrared rays that are invisible to the human eye.
NASA uses radio waves to communicate with missions beyond the Moon, but near-infrared light allows data to be packed into much denser waves, allowing more data to be sent and received. The DSOC experiment aims to demonstrate data rates 10 to 100 times faster than current radio frequency systems used by spacecraft today, according to NASA.
However, optical communication becomes more complex over longer distances as it requires extreme precision to direct the laser beam. The further the Psyche apparatus moves towards its target, the weaker the laser photon signal will be. Additionally, the photons will take longer to reach their destination, creating a delay of more than 20 minutes. By the time the data reaches Earth, ground control will have to adjust the spacecraft’s new position.
The test was the first to fully involve ground stations and the transmitter, requiring the DSOC and Psyche teams to work together. It was a difficult test and we still have a lot of work to do, but for a short time we were able to transmit, receive and decode some data.
Having completed the first test, the team will now work to improve the systems that control laser direction on board the transceiver.
