NASA Psyche Sets New Benchmark for Space Communications

NASA’s Psyche mission has achieved a new milestone in space-based communications.

Psyche and NASA’s Deep Space Optical Communications record

In December 2024, the spacecraft successfully transmitted an infrared laser message to Earth from an extraordinary 494 million kilometres (307 million miles) away. This is over twice the average distance between Earth and Mars, and more than 1,285 times farther than the Moon.

The achievement marks a major success for NASA’s Deep Space Optical Communications (DSOC) technology demonstration, which has been operating since the asteroid-bound spacecraft launched in 2023. Earth has now received Psyche’s 65th and final laser downlink, sent from 350 million kilometres (218 million miles) away.

The final transmission came from a shorter distance because Psyche is travelling in a solar orbit that takes it alternately nearer to, and farther from, Earth according to its alignment. The spacecraft is heading towards a 2029 encounter with the asteroid that shares its name.

From now on, Psyche will concentrate on its journey to the asteroid belt, relying on more conventional radio communications to transmit data back to Earth.

"NASA is setting America on the path to Mars, and advancing laser communications technologies brings us one step closer to streaming high-definition video and delivering valuable data from the Martian surface faster than ever before," says acting NASA Administrator Sean Duffy.

"Technology unlocks discovery, and we are committed to testing and proving the capabilities needed to enable the Golden Age of exploration."

DSOC laser communications performance

Overall, DSOC successfully delivered 13.6 terabytes of data to ground terminals on Earth. This included an ultra-high-definition video transmitted to Earth at 267 megabits per second from a distance exceeding 30.5 million kilometres, an historic first.

If humanity is to expand its activities in space, communications technology will need to improve. Radio links are dependable, but they are comparatively slow. Moreover, the Deep Space Network of radio antennas NASA uses to receive spacecraft data has already revealed capacity constraints that affect the agency’s ability to meet mission goals.

The challenges of deep-space laser signals

Sending laser signals is more complicated than producing radio transmissions. Radio signals spread relatively widely, meaning they do not require exceptionally precise aiming. Lasers, by contrast, form narrow, concentrated beams that must be aligned exactly with the intended receiver.

Light travelling through space also weakens and deteriorates, so less data can be recovered as the target becomes more distant. In April 2024, when Psyche was 225 million kilometres from Earth, its downlink speed had fallen to 25 megabits per second. Receivers must therefore be sensitive enough to identify the small stream of photons that reaches them.

Earth’s atmosphere and weather conditions can further disrupt signals before they arrive at ground stations. In time, space-based relays may be required to assist with receiving and storing data. For the present, though, the demonstration has established that DSOC technology functions and is sufficiently robust to transmit substantial quantities of data across deep space.

"NASA Technology tests hardware in the harsh environment of space to understand its limits and prove its capabilities," says Clayton Turner, associate administrator of NASA's Space Technology Mission Directorate.

"Over two years, this technology surpassed our expectations, demonstrating data rates comparable to those of household broadband internet and sending engineering and test data to Earth from record-breaking distances."

The result is highly encouraging and suggests strong prospects for communications with a future Mars mission, whenever it takes place. For the moment, Psyche is continuing farther into the Solar System towards another historic milestone.

Further information about DSOC is available on NASA’s website.