‘First light’: NASA receives laser-beamed message from 10 million miles away
An innovative experiment flying aboard NASA’s Psyche mission just hit its first major milestone by successfully carrying out the most distant demonstration of laser communications. The tech demo could one day help NASA missions probe deeper into space and uncover more discoveries about the origin of the universe.
Launched in mid-October, Psyche is currently en route to catch humanity’s first glimpse of a metal asteroid between the orbits of Mars and Jupiter. The spacecraft will spend the next six years traveling about 2.2 billion miles (3.6 billion kilometers) to reach its namesake, located in the outer part of the main asteroid belt.
Along for the ride is the Deep Space Optical Communications technology demonstration, or DSOC, which is carrying out a mission of its own during the first two years of the journey.
The tech demo was designed to be the US space agency’s most distant experiment of high-bandwidth laser communications, testing the sending and receiving of data to and from Earth using an invisible near-infrared laser. The laser can send data at 10 to 100 times the speed of traditional radio wave systems NASA uses on other missions. If wholly successful over the next couple of years, this experiment could be the future basis of technology that is used to communicate with humans exploring Mars.
And DSOC recently achieved what engineers called “first light,” the feat of successfully sending and receiving its first data.
The experiment beamed a laser encoded with data from far beyond the moon for the first time. The test data was sent from nearly 10 million miles (16 million kilometers) away and reached the Hale Telescope at the California Institute of Technology’s Palomar Observatory in Pasadena, California.
The distance between DSOC and Hale was about 40 times farther than the moon is from Earth.
“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 for the Space Technology Mission Directorate at NASA, in a statement.
Sending lasers across space
First light, which occurred on November 14, happened as the flight laser transceiver instrument on Psyche received a laser beacon sent from the Optical Communications Telescope Laboratory at NASA’s Jet Propulsion Laboratory’s Table Mountain Facility near Wrightwood, California.
The initial beacon received by Psyche’s transceiver helped the instrument aim its laser to send data back to the Hale Telescope, which is located about 100 miles (160 kilometers) south of Table Mountain.
“(The November 14) 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, located in Pasadena, California, in a statement. “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.”
It’s not the first time laser communications have been tested in space. The first test of two-way laser communication occurred in December 2021 when NASA’s Laser Communications Relay Demonstration launched and went into orbit about 22,000 miles (35,406 kilometers) from Earth.
Since then, experiments have sent optical communications from low-Earth orbit and to the moon. And the Artemis II spacecraft will use laser communications to return high-definition video of a crewed journey around the moon. But DSOC marks the first time laser communications have been sent across deep space, which requires incredibly precise aim and pointing over millions of miles.
The initial test of the tech demo’s capabilities will allow the team to work on refining the systems used in the laser’s pointing accuracy. Once the team has checked that box, DSOC will be ready to send and receive data to the Hale Telescope as the spacecraft travels farther from Earth.
Future challenges
While DSOC won’t actually send scientific data collected by the Psyche spacecraft because it’s an experiment, the laser will be used to send bits of test data encoded in the laser’s photons, or quantum light particles.
Detector arrays on Earth can pick up the signal from Psyche and extract the data from the photons. This kind of optical communication could change the way NASA sends and receives data from its missions across deep space.
“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 program, in a statement. “More data means more discoveries.”
As Psyche continues on its journey, more challenges await.
The DSOC team will be monitoring how long it takes for the laser messages to travel across space. During first light, it took only 50 seconds for the laser to travel from Psyche to Earth. At the farthest distance between the spacecraft and Earth, the laser is expected to take 20 minutes to travel one way. And during that time, the spacecraft will continue to move and Earth will rotate.
Meanwhile, the Psyche spacecraft continues to prepare for its primary mission, powering on propulsion systems and testing the scientific instruments it will need to study the asteroid when it arrives in July 2029. The mission could determine whether the asteroid is the exposed core of an early planetary building block from the beginning of the solar system.