Eventually, we’ll want to extend the World Wide Web across the entire galaxy, and NASA recently demonstrated a key technology that could help with that; it transmits messages with a laser from about 16 million kilometers (10 million miles) away.

That’s about 40 times farther than the Moon is from Earth, and the feat, achieved in November 2023, was the first time an optical link had been transmitted over such a distance.

Traditionally, we use radio waves to communicate with distant spacecraft, but higher frequencies of light, such as near-infrared, offer increased bandwidth and therefore huge increases in data rates.

If we can eventually send high-definition video messages to and from Mars without significant delay, it’s a step toward the technology we need. The test was part of NASA’s Deep Space Optical Communications (DSOC) experiment, and successful communication is known as “first light.”

“Reaching first light is one of the major milestones for DSOC in the coming months, paving the way for higher data rates capable of streaming scientific information, high-resolution imagery, and video that will support humanity’s next giant leap,” said Trudy Cortez, Technology Demonstration Director at NASA Headquarters.

We all rely on similar technology embedded in optical fibers for terrestrial high-speed communications, but here this technology has been adapted for use in deep space to improve current methods of transmitting information to Earth.

Because it is infrared light, engineers can easily transmit its waves in the form of lasers. This does not speed up the light’s travel, but rather regulates its beam and confines it to a narrow channel. It requires much less energy than emitting radio waves and is much harder to interfere with.

That doesn’t mean it’s an easy task. Data bits are encoded in photons emitted by the laser, which requires a series of high-powered devices, including a superconducting, high-efficiency detector array, to prepare the information for transmission and broadcast it to the other end.

Another challenge is having the system adapt its positioning configuration in real time. In the most recent test, it took about 50 seconds for laser photons to travel from the spacecraft to the telescope, while both spacecraft were hurtling through space.

The laser receiver that provides the link is on the Psyche spacecraft, which is on a long-term mission to the asteroid belt between Mars and Jupiter. It has linked up with the Hale telescope at Palomar Observatory in California.

Psyche is planned to fly to Mars, so tests will continue to develop and improve this innovative near-infrared communication method to ensure it is as fast and reliable as it needs to be.

“This was a huge challenge, and we still have a lot of work to do, but we were able to transmit, receive, and decode some data in a short period of time,” said Meera Srinivasan, DSOC operations director at NASA’s Jet Propulsion Laboratory.