On December 8, 2021, the National Aeronautics and Space Administration (NASA) launched its new Laser Communications Relay Demonstration (LCRD) into space from Cape Canaveral Space Force Station, Florida, on an Atlas V rocket of the United Launch Alliance. It is NASA’s first-ever laser communication system to study Sun’s radiation and will help the agency’s testing of optical communications in space.
LCRD is part of the Space Test Program 3 mission, a joint venture between the US Space Force and NASA. It is expected that the new laser communications technology will expand the possibilities of gathering more correct information about the solar system. The LCRD will showcase the unique capabilities of optical communication, compared to most NASA missions which have been successfully using radio frequency communications to send data to and from spacecraft since the beginning of space exploration. However, the need for enhanced communications capabilities becomes essential as space missions generate and collect more data.
The LCRD was developed by NASA’s Goddard Space Flight Center and is flying aboard a US Department of Defense Space Test Program Satellite 6 (STPSat-6) spacecraft. It would be in a geosynchronous orbit, (22,000 miles) or more than 35,000 km above the Earth.
Advantages of LCRD
The LCRD would send and receive data over invisible infrared lasers and will demonstrate NASA’s first two-way laser relay communication’s system. Thus, optical communication will help and enable data rates from 10 to 100 times greater than the traditional radio frequency systems. It would also prevent overcrowding of the radio frequency spectrum, which has been happening over the past few decades because of rapidly increasing constellations of satellites in the low Earth orbits.
The LCRD would send and receive data at a rate of 1.2 gigabits per second from geosynchronous orbit to the Earth. This communication system is smaller, lighter, and uses less power than radio frequency systems. A smaller size means more room for science instruments; lesser weight means less expenses of launching; and lesser consumption of power means less drainage of batteries. Besides, higher bandwidth of LCRD could advance robotic and human exploration across the solar system.
The LCRD would pave the way for future optical communications missions which could potentially use LCRD as their relay. LCRD’s first operational users include the Integrated LCRD Low-Earth Orbit User Modem and Amplifier Terminal (ILLUMA-T), a payload that would be hosted on the International Space Station. The terminal would receive high-resolution science data from experiments and instruments onboard the space station and then transfer this data to LCRD which would transmit it to a ground station from where it would be delivered to mission operation centres and mission scientists.
The LCRD would conduct various experiments in the space for two years. It would assess how weather and other changes in Earth’s atmosphere could impact laser communications, and measure link performance for refinement of operations and process.
According to deputy associate administrator for NASA’s Space Communications and Navigation (SCaN) programme at NASA Headquarters, Badri Younes, the LCRD is NASA’s key milestone for the build-up of the ‘Decade of Light’ initiative, involving the infusion of optical technology into space communications and navigation. By the 2030s, optical technology is expected to play a critical role in enabling an interoperable, reliable, and robust space communications infrastructure, which would provide seamless operations and roaming capability between government and commercial users and providers.
However, unlike radio frequency communications, optical signals cannot penetrate cloud coverage. Therefore, NASA must build a system flexible enough to avoid interruptions due to weather. The LCRD will transmit data, received from missions, to two ground stations, located in Table Mountain in California, and in Haleakala Hawaii, chosen for their minimal cloud coverage. It will also test different cloud coverage scenarios, gathering valuable information about the space.
Laser vs Radio Communication Technology
LCRD communications and radio communications technology use different wavelengths of light. LCRD uses infrared light and has a shorter wavelength than radio waves. This will help the transmission of more data in shorter time. As per NASA, current radio frequency systems would take roughly nine weeks to transmit a completed map of Mars back to Earth, while LCRD do that very quickly, in about nine days.
In short, missions will have unparalleled communications capabilities with the development of LCRD.
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