A deep-space experiment aboard NASA’s Psyche spacecraft has just sent a laser message to Earth from a distance from the moon for the first time, a feat that could change how spacecraft communicate.
In the farthest demonstration ever of this type of optical communication, Deep Space Optical Communications (DSOC) beamed a near-infrared laser encoded with test data from its location about 16 million kilometers (10 million miles) away — about 40 times as far as . Farther from the Moon than Earth – to the Hale Telescope at Caltech’s Palomar Observatory in California.
DSOC is a two-year technology demonstration riding on Psyche as it makes its way to its main target, the asteroid Psyche. The demonstration achieved “first light” on November 14, according to NASA’s Jet Propulsion Laboratory (JPL), which manages both missions, thanks to an incredibly precise maneuver that saw the laser transceiver lock on to JPL’s powerful uplink laser beacon in Table Mountain Observatory. This allowed DSOC’s transceiver to aim its downlink laser at the Caltech Observatory 130 kilometers (100 mi) away.
“Achieving first light is one of many important milestones for DSOC in the coming months, paving the way toward higher data rate communications capable of sending scientific information, high-definition images and streaming video to support humanity’s next giant leap: sending humans,” said Trudy Curtis, Promotion Director. Technology at NASA headquarters, in a press conference: “To Mars.” statement.
Optical communication was used to send messages From Earth’s orbit before, but this is the furthest distance so far with lasers. In a laser beam, the beam of photons moves in the same direction and with the same wavelength. Laser communications can transmit massive amounts of data at unprecedented speeds by packaging the data into the oscillations of these light waves, and encoding an optical signal that can transmit messages to a receiver via infrared rays (invisible to humans).
You can see DSOC’s gold-covered flight laser transceiver on Psyche when it was located at NASA’s Astrotech Space Operations facility in December 2022.
Image credit: NASA/Ben Smigelski
NASA typically uses radio waves to communicate with missions farther from the Moon, both of which use electromagnetic waves to transmit data, but the advantage of lasers is that more data can be packed into more compact waves. According to NASA, the DSOC technology demonstration aims to demonstrate transmission rates 10 to 100 times greater than the best current radio communications systems.
Allowing more data to be transmitted will allow future missions to carry higher-resolution science instruments as well as allow for faster communications on potential deep space missions – for example, live video streaming from the surface of Mars.
“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 Program. . “More data means more discoveries.”
However, there are some challenges that need to be tested first. The further the optical connection has to travel, the more difficult it becomes, because it requires extreme precision to direct the laser beam. Also, the photons’ signal will become fainter, taking longer to reach their destination, ultimately creating communication delays.
During the test on November 14, photons took about 50 seconds to travel from Psyche to Earth. By the time Psyche reaches its farthest distance, it will take about 20 minutes to move back, long enough for both Earth and the spacecraft to move, so the lasers on both need to adapt to this change in position.
So far, the record-breaking technology demonstration has been a huge success. “[The] “The 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.”
Or as Abi Biswas, a DSOC project technologist at JPL, said: “[We] They were able to exchange “bits of light” to and from deep space. Exchanging bits of light to and from deep space may be a future change to how we communicate in space exploration.
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