NASA achieves historic data exchange with deep space optical communications experiment

DSOC, an experiment that could change how spacecraft communicate, has achieved “first light,” sending data via laser to and from beyond the Moon for the first time.

NASA’s Deep Space Optical Communications (DSOC) experiment 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 Palomar. Of the California Institute of Technology. Observatory in San Diego County, California. This is the farthest display ever of optical communications.

Aboard the recently launched Psyche spacecraft, DSOC is set to send high-bandwidth test data back to Earth during its two-year technology demonstration as Psyche travels to the main Earth-Earth asteroid belt. Mars And Jupiter. NASAjet propulsion laboratory (Jet Propulsion Laboratory_In Southern California he runs 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 Dec. 8, 2022. DSOC’s gold-covered aviation laser transceiver can be seen, near the center, attached to the spacecraft. Credit: NASA/Ben Smigelsky

The technology demonstration achieved “first light” in the early hours of 14 November after the Aviation Laser Transceiver – a cutting-edge instrument (see image below) aboard Psyche capable of sending and receiving near-infrared signals – was installed on a powerful laser beacon. The uplink was transmitted from the Optical Communications Telescope Laboratory at JPL’s Table Mountain Facility near Wrightwood, California. The uplink beacon helped the transceiver point its downlink laser at Palomar (100 miles, or 130 kilometers, south of Table Mountain) while automated systems on the transceiver and ground stations adjusted its pointing.

The Deep Space Optical Communications (DSOC) laser transceiver is on display at NASA’s Jet Propulsion Laboratory in Southern California in April 2021, before being installed inside its boxy housing that was later integrated with NASA’s Psyche spacecraft. The transceiver consists of a near-infrared laser transmitter to send high-speed data to Earth, and a sensitive photon counting camera to receive low-speed data sent from Earth. The transceiver is mounted on a set of struts and actuators — shown in this image — that stabilize the optics from the spacecraft’s vibrations. Image source: NASA/JPL-Caltech

“Achieving first light is one of many important DSOC milestones in the coming months, paving the way toward higher data rate communications capable of transmitting scientific information, high-definition images and video streaming to support humanity’s next giant leap: Sending humans to Marssaid Trudy Curtis, technology demonstration manager at NASA Headquarters in Washington.

Test data was also transmitted simultaneously via uplink and downlink lasers, a procedure known as “link closure” that is the primary goal of the experiment. Although the technology demonstration does not transmit Psyche mission data, it works closely with the Psyche mission support team to ensure DSOC operations do not interfere with spacecraft operations.

Learn more about how DSOC is being used to test high-bandwidth data transmission beyond the Moon for the first time — and how it could transform deep space exploration. Image source: NASA/JPL-Caltech/Arizona State University

“Tuesday morning’s test was the first to fully integrate ground and flight transponder assets, requiring the DSOC and Psyche operations teams to work side by side,” said Meera Srinivasan, DSOC operations lead at JPL. “It was a huge challenge, and we have a lot of work to do, but for a short time, we were able to send, receive and decrypt some data.”

Before this milestone, the project needed to tick the boxes of several other milestones, from removing the protective cover of the aviation laser transceiver to commissioning the device. Meanwhile, the Psyche spacecraft is performing its own checks, including operating its propulsion systems and test instruments that will be used to study asteroid Psyche when it arrives there in 2028.

NASA’s Deep Space Optical Communications (DSOC) laser transceiver operations team is working in the Psyche mission support area at JPL in the early hours of November 14, when the project achieved “first light.” Image source: NASA/JPL-Caltech

First light and first bits

With the success of First Light, the DSOC team will now work to improve the systems that control the pointing of the downlink laser on board 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 laser photons – quantum particles of light. After a special, highly efficient superconducting detector array (see image below) detects the photons, new signal processing techniques are used to extract data from single photons arriving at the Hale telescope.

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

The DSOC experiment aims to demonstrate data transfer rates 10 to 100 times greater than modern radio frequency systems used by spacecraft today. Both laser radio and near-infrared communications use electromagnetic waves to transmit data, but near-infrared light packs the data into more compact waves, enabling ground stations to receive more data. This will help with future human and robotic exploration missions and support high-precision scientific instruments.

“Optical communication is a boon to 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 in NASA’s Communications and Astronautics Division. (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, directing a laser beam over millions of miles requires extremely precise “pointing.”

DSOC’s ground-based 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’s “first light” demonstration was achieved on Nov. 14. Image source: NASA/JPL-Caltech

The demonstration also needs to compensate for the time it takes light to travel from the spacecraft to Earth over vast distances: at Psyche’s furthest distance from our planet, DSOC’s near-infrared photons would take about 20 minutes to return (it took about 50 minutes). seconds to travel from Psyche to Earth during the November 14 test). By that time, the spacecraft and planet will have moved, so the uplink and downlink lasers must adapt to the change in position.

“Achieving first light is a tremendous accomplishment. Ground systems have successfully detected deep space laser photons from DSOC’s transceiver aboard Psyche,” said Abi Biswas, DSOC project technologist at JPL. “Sending some data, which meant we were able to exchange ‘bits of light’ to and from deep space.”

More about the mission

DSOC is the latest in a series of optical communications 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 overall mission management, system engineering, integration and test, and mission operations. Psyche is the 14th mission selected as part of NASA’s Exploration Program under the Science Mission Directorate, which is managed by the agency’s Marshall Space Flight Center in Huntsville, Alabama. NASA’s Launch Services Program, headquartered at the agency’s Kennedy Space Center, managed the launch service. Maxar Technologies of Palo Alto, California, provided the spacecraft’s high-energy solar electric propulsion structure.