10 Million Miles Away: NASA Achieves Historic Data Exchange With Deep Space Optical Communications Experiment

DSOC, an experiment that could transform how spacecraft communicate, has achieved ‘first light,’ sending data via laser to and from far beyond the Moon for the first time.

NASA’s Deep Space Optical Communications (DSOC) experiment has beamed a near-infrared laser encoded with test data from nearly 10 million miles (16 million kilometers) away – about 40 times farther than the Moon is from Earth – to the Hale Telescope at Caltech’s Palomar Observatory in San Diego County, California. This is the farthest-ever demonstration of optical communications.

Riding aboard the recently launched Psyche spacecraft, DSOC is configured to send high-bandwidth test data to Earth during its two-year technology demonstration as Psyche travels to the main asteroid belt between MarsMars is the second smallest planet in our solar system and the fourth planet from the sun. It is a dusty, cold, desert world with a very thin atmosphere. Iron oxide is prevalent in Mars' surface resulting in its reddish color and its nickname "The Red Planet." Mars' name comes from the Roman god of war.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>Mars and JupiterJupiter is the largest planet in the solar system and the fifth planet from the sun. It is a gas giant with a mass greater then all of the other planets combined. Its name comes from the Roman god Jupiter.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>Jupiter. NASAEstablished in 1958, the National Aeronautics and Space Administration (NASA) is an independent agency of the United States Federal Government that succeeded the National Advisory Committee for Aeronautics (NACA). It is responsible for the civilian space program, as well as aeronautics and aerospace research. Its vision is "To discover and expand knowledge for the benefit of humanity." Its core values are "safety, integrity, teamwork, excellence, and inclusion." NASA conducts research, develops technology and launches missions to explore and study Earth, the solar system, and the universe beyond. It also works to advance the state of knowledge in a wide range of scientific fields, including Earth and space science, planetary science, astrophysics, and heliophysics, and it collaborates with private companies and international partners to achieve its goals.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>NASA’s Jet Propulsion Laboratory (JPLThe Jet Propulsion Laboratory (JPL) is a federally funded research and development center that was established in 1936. It is owned by NASA and managed by the California Institute of Technology (Caltech). The laboratory's primary function is the construction and operation of planetary robotic spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA's Deep Space Network. JPL implements programs in planetary exploration, Earth science, space-based astronomy and technology development, while applying its capabilities to technical and scientific problems of national significance.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>JPL_ in Southern California manages both DSOC and Psyche.

NASA’s Psyche spacecraft is shown in a clean room at the Astrotech Space Operations facility near the agency’s Kennedy Space Center in Florida on December 8, 2022. DSOC’s gold-capped flight laser transceiver can be seen, near center, attached to the spacecraft. Credit: NASA/Ben Smegelsky

The tech demo achieved “first light” in the early hours of November 14 after its flight laser transceiver – a cutting-edge instrument (see image below) aboard Psyche capable of sending and receiving near-infrared signals – locked onto a powerful uplink laser beacon transmitted from the Optical Communications Telescope Laboratory at JPL’s Table Mountain Facility near Wrightwood, California. The uplink beacon helped the transceiver aim its downlink laser back to Palomar (which is 100 miles, or 130 kilometers, south of Table Mountain) while automated systems on the transceiver and ground stations fine-tuned its pointing.

The Deep Space Optical Communications (DSOC) technology demonstration’s flight laser transceiver is shown at NASA’s Jet Propulsion Laboratory in Southern California in April 2021, before being installed inside its box-like enclosure that was later integrated with NASA’s Psyche spacecraft. The transceiver consists of a near-infrared laser transmitter to send high-rate data to Earth, and a sensitive photon-counting camera to receive ground-transmitted low-rate data. The transceiver is mounted on an assembly of struts and actuators – shown in this photograph – that stabilizes the optics from spacecraft vibrations. Credit: NASA/JPL-Caltech

“Achieving first light is one of many critical DSOC milestones in the coming months, paving the way toward higher-data-rate communications capable of sending scientific information, high-definition imagery, and streaming video in support of humanity’s next giant leap: sending humans to Mars,” said Trudy Kortes, director of Technology Demonstrations at NASA Headquarters in Washington.

Test data also was sent simultaneously via the uplink and downlink lasers, a procedure known as “closing the link” that is a primary objective for the experiment. While the technology demonstration isn’t transmitting Psyche mission data, it works closely with the Psyche mission-support team to ensure DSOC operations don’t interfere with those of the spacecraft.

[embedded content]
Learn more about how DSOC will be used to test high-bandwidth data transmission beyond the Moon for the first time – and how it could transform deep space exploration. Credit: NASA/JPL-Caltech/ASU

“Tuesday morning’s test was the first to fully incorporate the ground assets and flight transceiver, requiring the DSOC and Psyche operations teams to work in tandem,” said Meera Srinivasan, operations lead for DSOC at JPL. “It was a formidable challenge, and we have a lot more work to do, but for a short time, we were able to transmit, receive, and decode some data.”

Before this achievement, the project needed to check the boxes on several other milestones, from removing the protective cover for the flight laser transceiver to powering up the instrument. Meanwhile, the Psyche spacecraft is carrying out its own checkouts, including powering up its propulsion systems and testing instruments that will be used to study the asteroid Psyche when it arrives there in 2028.

The flight laser transceiver operations team for NASA’s Deep Space Optical Communications (DSOC) technology demonstration works in the Psyche mission support area at JPL in the early hours of November 14, when the project achieved “first light.” Credit: NASA/JPL-Caltech

First Light and First Bits

With successful first light, the DSOC team will now work on refining the systems that control the pointing of the downlink laser aboard the transceiver. Once achieved, the project can begin its demonstration of maintaining high-bandwidth data transmission from the transceiver to Palomar at various distances from Earth. This data takes the form of bits (the smallest units of data a computer can process) encoded in the laser’s photons – quantum particles of light. After a special superconducting high-efficiency detector array (see image below) detects the photons, new signal-processing techniques are used to extract the data from the single photons that arrive at the Hale Telescope.

Shown here is an identical copy of the Deep Space Optical Communications, or DSOC, superconducting nanowire single-photon detector that is coupled to the 200-inch (5.1-meter) Hale Telescope located at Caltech’s Palomar Observatory in San Diego County, California. Built by the Microdevices Laboratory at NASA’s Jet Propulsion Laboratory in Southern California, the detector is designed to receive near-infrared laser signals from the DSOC flight transceiver traveling with NASA’s Psyche mission in deep space as a part of the technology demonstration. Credit: NASA/JPL-Caltech

The DSOC experiment aims to demonstrate data transmission rates 10 to 100 times greater than the state-of-the-art radio frequency systems used by spacecraft today. Both radio and near-infrared laser communications utilize electromagnetic waves to transmit data, but near-infrared light packs the data into significantly tighter waves, enabling ground stations to receive more data. This will help future human and robotic exploration missions and support higher-resolution science instruments.

“Optical communication is a boon for scientists and researchers who always want more from their space missions, and will enable human exploration of deep space,” said Dr. Jason Mitchell, director of the Advanced Communications and Navigation Technologies Division within NASA’s Space Communications and Navigation (SCaN) program. “More data means more discoveries.”

While optical communication has been demonstrated in low Earth orbit and out to the Moon, DSOC is the first test in deep space. Like using a laser pointer to track a moving dime from a mile away, aiming a laser beam over millions of miles requires extremely precise “pointing.”

DSOC ground laser transmitter operators pose for a photo at the Optical Communications Telescope Laboratory at JPL’s Table Mountain Facility near Wrightwood, California, shortly after the technology demonstration achieved “first light” on November 14. Credit: NASA/JPL-Caltech

The demonstration also needs to compensate for the time it takes for light to travel from the spacecraft to Earth over vast distances: At Psyche’s farthest distance from our planet, DSOC’s near-infrared photons will take about 20 minutes to travel back (they took about 50 seconds to travel from Psyche to Earth during the Nov. 14 test). In that time, both spacecraft and planet will have moved, so the uplink and downlink lasers need to adjust for the change in location.

“Achieving first light is a tremendous achievement. The ground systems successfully detected the deep space laser photons from DSOC’s flight transceiver aboard Psyche,” said Abi Biswas, project technologist for DSOC at JPL. “And we were also able to send some data, meaning we were able to exchange ‘bits of light’ from and to deep space.”

More About the Mission

DSOC is the latest in a series of optical communication demonstrations funded by NASA’s Space Technology Mission Directorate and the Space Communications and Navigation (SCaN) program within the agency’s Space Operations Mission Directorate.

The Psyche mission is led by Arizona State University. JPL is responsible for the mission’s overall management, system engineering, integration and test, and mission operations. Psyche is the 14th mission selected as part of NASA’s Discovery Program under the Science Mission Directorate, managed by the agency’s Marshall Space Flight Center in Huntsville, Alabama. NASA’s Launch Services Program, based at the agency’s Kennedy Space Center, managed the launch service. Maxar Technologies in Palo Alto, California, provided the high-power solar electric propulsion spacecraft chassis.