NASA Completes First Laser Link Between Earth and Space Terminals; Two-Way Beam Experiment Could Aid Future Missions in Moon and Mars

The success of every space mission relies heavily on navigation systems and reliable space communication. Every day, NASA receives and sends images. spacecraft commands, and scientific data through giant antennas on Earth.

The agency currently uses radio waves for communication, but it also explores the possibility of connecting with infrared lasers. Just recently, NASA made a groundbreaking discovery when it completed its first laser link.

Successful Laser Experiment

On December 5, NASA successfully demonstrated two-way laser communications between laser terminals in different orbits. The completion of the first laser link with an in-orbit laser relay system marks a significant breakthrough in space communication technology, especially between Earth and the moon or even beyond.

Experts took years to set up the experiment. On November 9, the Integrated LCRD Low Earth Orbit User Modem and Amplifier Terminal (ILLUMA-T) payload was delivered to the International Space Station (ISS). It was launched aboard a SpaceX Falcon rocket as part of NASA's 29th commercial resupply services mission.

After installing the payload to the Japanese Experiment Module-Exposed Facility, engineers conducted tests to ensure the functionality of ILLUMA-T. Then it was used to communicate with NASA's Laser Communications Relay Demonstration (LCRD) satellite which was launched in 2021 to operate high up in geostationary orbit.

While the International Space Station orbits around 230-275 miles (370-460 kilometers) above the Earth, LCRD orbits at 22,236 miles (35,786 kilometers) above the equator. This gap enables long distance tests of laser communications.

Both ILLUMA-T and LSRC belong to NASA Space Communications and Navigation (SCaN) program. NASA believes that the use of laser communications greatly increases the efficiency of data transfer and can lead to a faster pace of scientific discoveries.

According to SCaN's Advanced Communications and Navigation Technology division director Dr. Jason Mitchell, laser communications will not only return more data from space missions, but they could also serve as a critical, two-way link to connect the astronauts to Earth as they explore the Solar System. Meanwhile, NASA space communications and navigation architect David Israel reported that their team is now performing operational demonstrations and experiments which will enable them to optimize their infusion of proven technology into their missions to maximize space exploration.

How Does Spaced-Based Laser Communication Work?

Laser communication refers to the use of modulated laser beams to send and receive information wirelessly between two points. Also known as optical communications, it uses infrared light instead of traditional radio waves to send and receive signals. The shorter wavelengths of infrared lasers enable much greater amounts of information to be sent with each transmission compared with the longer wavelengths of radio waves.

Laser light operates at 200 terahertz, a higher frequency compared to a few gigahertz for radio waves. This allows more information packets to be encoded per second on the higher frequency carrier beam.

Aside from speed, laser communication offers other advantages such as miniaturization of space communication hardware. It also reduces power consumption since the focused beams minimizes power waste from spreading or absorption. Lastly, the directionality of laser beams makes optical communication more secure, unlike radio frequency channels which are vulnerable to interception and jamming.