This Month in Science

Communication with Space

Astronauts in space need to be able to communicate with mission control in Houston, Texas at all times. Maintaining communication is one of the great challenges of sending people into space. Whether it’s a crisis, like the explosion during the Apollo 13 mission, or just a routine check-in aboard the International Space Station (ISS), astronauts must have a functioning communication system.

From the very first Mercury mission, the National Aeronautics and Space Administration (NASA) has relied on radio waves to communicate with astronauts and transmit data to Earth. Radio waves work well for this, but as missions generate and collect more data, engineers need to transmit more data at faster rates. NASA is developing communication systems using infrared lasers, called optical communications. Infrared light allows for 10-100 times more data to be transmitted at a time compared to radio systems. Later this year, NASA engineers and astronauts aboard the ISS will test this new, faster form of data transmission and space communication that uses light waves instead of radio waves.

Radio and light are both wave frequencies on the electromagnetic spectrum. NASA currently uses radio waves for all communication and data transmission. When an astronaut needs to speak with mission control, their voice gets encoded into a radio wave that is then transmitted to a receiver on the ground. Astronauts also send results from experiments back to Earth and receive information from mission control, like daily work schedules and status updates about the ISS itself. Mars rovers, like Curiosity, transmit data about the geology and landscape of the planet. Even deep space probes, like Voyager 1—which is 14.8 billion miles away from our planet—are still sending information back to Earth via radio waves.

In order to transmit larger amounts of data at a faster rate of transfer, NASA engineers are currently testing a new communication satellite that uses light waves. The satellite is called the Laser Communications Relay Demonstration (LCRD) and uses beams of infrared light to transmit data. Like radio waves, infrared light is also invisible, but unlike radio, it has a much higher frequency. This higher frequency allows scientists and engineers to encode more data into each transmission. Think of it like upgrading your internet from dial-up to fiber optic.

Communication with light waves is not without challenges. Light waves need a direct line of sight to transmit data, but infrared lasers spread out less than radio waves, making it easier to direct the beam and avoid interference with other satellites. Cloud cover, space junk, aircraft, and anything else that breaks the laser beam can disrupt communication. Part of the testing for LCRD will be conducting studies on cloud coverage to determine what level breaks the connection. NASA also tracks space junk and makes sure the operating area is clear of aircraft for data transmission.

The space station will be getting a laser relay called Integrated LCRD Low Earth Orbit User Modem and Amplifier Terminal (ILLUMA-T) later this year. ILLUMA-T will allow the ISS to send data via laser light to the LCRD at rates of 1.2 gigabits per second to be transmitted back to Earth. This relay system will vastly improve transmission between Earth and the space station making communication to and from space faster.

For more updates on LCRD, check NASA’s site. To participate in a citizen science project that helps NASA track cloud cover, check out the GLOBE Observer program.

Previous Columns

December: Christmas Bird Count
September: The Longleaf Pine
July: Sea Turtle Season
May: Ghost Trees
March: Jellyfish
January 2022: Venus Flytrap
November: Citizen Science
September: Hurricane Season
July: Plastic Free July
June: All About Alligators
May: Rain Gardens
April: Bald Cypress Trees and The Climate Record
March: Ocean Waves
February: The Scientific Method
January 2021: Static Electricity