The revolutionary optical communication in deep space
NASA recently made a significant step forward in the field of space communications, thanks to the Deep Space Optical Communications (DSOC) optical communication experiment aboard the Psyche spacecraft. This technology, which does not rely on traditional radio communications, has been shown to be capable of transmitting engineering data from the impressive distance of more than 140 million miles (226 million kilometers), exceeding 1.5 times the distance between the Earth and the Sun.
This achievement opens up new perspectives for the future of space communications, enabling the transmission of complex scientific information and high-definition images and videos, which will be crucial for humanity’s next great leap: sending humans to Mars.
Exceeding expectations with laser technology
NASA’s optical communications demonstration demonstrated the ability to transmit test data at a maximum rate of 267 megabits per second (Mbps) using the flight laser transmitter’s near-infrared laser, a bit rate comparable to broadband internet download speeds.
On December 13, 2023, the experiment transmitted a 15-second ultra high-definition video to Earth from a distance of 19 million miles (31 million kilometers), about 80 times the Earth-Moon distance. The video, along with other test data, had been uploaded to the flight laser transmitter before Psyche’s launch last year.
Now that the spacecraft is more than seven times farther away, the speed of transmitting and receiving data has slowed, as expected. During the April 8 test, the spacecraft transmitted test data at a maximum rate of 25 Mbps, far exceeding the project’s goal of demonstrating that at least 1 Mbps was possible at that distance.
Fun with lasers in deep space
After Psyche’s launch, the optical communications demonstration was initially used to transmit pre-loaded data, including videos of Taters the cat. Since then, the project has demonstrated that the transmitter can receive data from the powerful uplink laser at JPL’s Table Mountain facility near Wrightwood, California. Data can also be sent to the transmitter and then broadcast back to Earth on the same night, as demonstrated in a recent “turnaround experiment.”
This experiment transmitted test data – as well as digital photographs of pets – to Psyche and back again, a round trip of up to 280 million miles (450 million kilometers). It also transmitted large quantities of technology demonstration engineering data to study the characteristics of the optical communication link.
“We’ve learned a lot about how much we can push the system when we have clear skies, although storms have disrupted operations at both Table Mountain and Palomar on occasion,” said Ryan Rogalin, receiver electronics manager of the project at JPL.
Psyche mission details
The demonstration, managed by JPL, is the latest in a series of optical communications experiments funded by the Technology Demonstration Missions (TDM) program under the direction of the NASA Space Technology Mission and the Space Communications and Navigation (SCaN) program. within the Space Operations Mission Directorate. Flight laser transmitter development is supported by MIT Lincoln Laboratory, L3 Harris, CACI, First Mode and Controlled Dynamics Inc., and Fibertek, Coherent and Dotfast support ground systems. Some of the technology was developed through NASA’s Small Business Innovation Research program.
Arizona State University is leading the Psyche mission. JPL is responsible for overall mission management, system engineering, integration, and mission test and operations. Psyche is the 14th mission selected as part of NASA’s Discovery program under the direction of the Science Mission, operated from the agency’s Marshall Space Flight Center in Huntsville, Alabama. NASA’s Launch Services Program, headquartered at the agency’s Kennedy Space Center in Florida, handled the launch service. Maxar Technologies has supplied the high-power solar electric propulsion spacecraft chassis from Palo Alto, California.
