[Laser] NASA Deep Space Optical Comms Demo Sends/Receives Data Across 16 Million Kilometers

[bernieS]

https://www.jpl.nasa.gov/news/nasas-deep-space-optical-comm-demo-sends-receives-first-data

NASA’s Deep Space Optical Comm Demo Sends, Receives First Data

Nov. 16, 2023

(Photo) 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-capped 
flight laser transceiver can be seen, near 
center, attached to the spacecraft. Credit: NASA/Ben Smegelsky

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 Mars 
and Jupiter. NASA’s Jet Propulsion Laboratory in 
Southern California manages both DSOC and Psyche.

The tech demo achieved “first light” in the early 
hours of Nov. 14 after its flight laser 
transceiver – a cutting-edge instrument 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.

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
“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.

“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.

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 detects the photons, new signal-processing 
techniques are used to extract the data from the 
single photons that arrive at the Hale Telescope.

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.”

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.

For more information about DSOC, visit:  https://www.jpl.nasa.gov/missions/dsoc