NASA has a new trick up its sleeve for space communication. In July 2024, the Deep Space Optical Communications (DSOC) technology demonstration beamed a laser signal to the Psyche spacecraft, which was soaring approximately 290 million miles from Earth — a distance comparable to the gap between our planet and Mars at its farthest.
This record-breaking laser-based transmission, reaching across such a vast expanse of the cosmos, is redefining what’s possible in deep-space data exchange.
Space communication finally enters a new era
For most of space exploration’s history, missions have relied on radio waves to send data back to Earth. Although reliable, radio waves have limitations, especially as we venture farther from home. With DSOC, NASA is aiming to leap beyond these constraints.
Laser communication in space is much faster than conventional radio transmissions — think of it as upgrading from dial-up to broadband, but on a galactic scale. Credit: NASA/JPL-Caltech.
“The milestone is significant. Laser communication requires a very high level of precision, and before we launched with Psyche, we didn’t know how much performance degradation we would see at our farthest distances,” explains Meera Srinivasan, the project’s operations lead at NASA’s Jet Propulsion Laboratory (JPL) in Southern California. “Now the techniques we use to track and point have been verified, confirming that optical communications can be a robust and transformative way to explore the solar system.”
The DSOC system aboard the Psyche spacecraft pairs with two ground stations on Earth to send and receive data via laser. The Hale Telescope at Caltech’s Palomar Observatory serves as the downlink station, capturing the spacecraft’s transmissions from space. Meanwhile, the Optical Communications Telescope Laboratory at JPL’s Table Mountain facility, capable of transmitting 7 kilowatts of laser power, acts as the uplink.
Why a laser? Light-based communication, compared to radio waves, can transport data much faster. In fact, it’s about 100-fold faster. At about 33 million miles from Earth — similar to Mars’ closest approach — the DSOC system achieved a maximum transfer speed of 267 megabits per second. This is about as fast as a broadband connection on Earth. Even at distances of 240 million miles, DSOC managed a sustained 6.25 megabits per second, with peaks reaching 8.3.
By comparison, a traditional radio system wouldn’t come close to these speeds at such distances. We all enjoy the pictures and science beamed back by NASA’s rovers on Mars, but we rarely get to think about how much effort and time is wasted. Imagine how much more we could learn from Mars if communication wasn’t restricted by the equivalent of interplanetary dial-up networks.
Testing the Potential of Light-Speed Data
The laser-powered DSOC system isn’t just fast — it’s versatile. NASA’s Psyche mission team took the opportunity to send unique data. This included artwork from Arizona State University’s “Psyche Inspired” project, a 45-second ultra-high-definition video spoofing vintage TV test patterns, and even images of the team’s pets. Encoded in near-infrared light, these transmissions pushed DSOC’s capabilities to handle varied, complex data types.
“A key goal for the system was to prove that the data-rate reduction was proportional to the inverse square of distance,” says Abi Biswas, the project’s technologist at JPL. In simpler terms, the farther Psyche traveled, the more the data rate predictably slowed, yet still far outpaced radio transmission limits. During the first phase of testing alone, DSOC managed to downlink nearly 11 terabits of data — proof that this laser system could send massive volumes across immense space.
The project hit another milestone on June 24 when it transmitted a high-definition video featuring a cat named Taters from 240 million miles away. It was a light-hearted demonstration of serious capabilities, showing how laser communication could support future missions involving real-time, high-definition video streams from distant planets and moons.
After reaching its primary goals, DSOC’s flight transceiver powered down temporarily, before it was reactivated in November for a final operational phase. This final test aims to confirm the transceiver’s durability over extended missions, exceeding one year.
“Once that’s achieved, we can look forward to operating the transceiver at its full design capabilities during our post-conjunction phase that starts later in the year,” says Ken Andrews, the project’s flight operations lead at JPL
