NASA has achieved a remarkable feat of deep space communication by receiving a laser message from 10 million miles away. This is the farthest distance that optical communication has ever been demonstrated, and it could revolutionize how we communicate with spacecraft in the future.
What is optical communication?
Optical communication is a way of transmitting data using light waves, such as near infrared, instead of radio waves. Light waves have higher frequencies and can carry more information than radio waves, which means they can enable faster and higher-quality data transmission.
Optical communication is already widely used on Earth, through fiber optic cables that carry internet and phone signals. However, using it in space is much more challenging, because of the distance, the movement, and the interference from the atmosphere.
How did NASA do it?
NASA’s Deep Space Optical Communications (DSOC) experiment is the first demonstration of optical communication beyond the Moon. It is part of NASA’s Psyche mission, which launched on October 13, 2023, to explore a metal-rich asteroid in the asteroid belt.
The DSOC experiment consists of a flight laser transceiver on board the Psyche spacecraft, a ground laser transmitter, and a ground laser receiver. The flight laser transceiver sends a near infrared laser beam encoded with test data to Earth, where it is detected by the ground laser receiver at the Hale Telescope at Caltech’s Palomar Observatory in California.
The test data was successfully received on November 21, 2023, after traveling nearly 10 million miles (16 million kilometers) in about 50 seconds. This distance is about 40 times farther than the Moon is from Earth, and it is expected to increase as the Psyche spacecraft continues its journey to the asteroid belt.
The DSOC experiment also has to overcome several technical challenges, such as keeping the laser beam aligned and stable, compensating for the Doppler effect caused by the relative motion of the spacecraft and Earth, and filtering out noise and background light.
Why is it important?
Optical communication could enable faster and better data transmission for future space missions, especially for human exploration of Mars and beyond. It could allow sending scientific information, high-definition imagery, and streaming video in support of humanity’s next giant leap.
Optical communication could also reduce the power consumption and mass of spacecraft communication systems, which could free up more resources for other scientific instruments and experiments.
NASA plans to continue testing and improving the DSOC experiment in the coming months, paving the way for higher-data-rate communications in deep space.