3 min readNew DelhiDec 9, 2021 09:29 AM IST
First published on: Dec 7, 2021 at 09:01 PM IST
On December 7, around 3.50 pm IST, NASA launched its new Laser Communications Relay Demonstration (LCRD) — the agency’s first-ever laser communications system — from Cape Canaveral Space Force Station in Florida. The LCRD will help the agency test optical communication in space.
Currently, most NASA spacecraft use radio frequency communications to send data. Optical communications will help increase the bandwidth 10 to 100 times more than radio frequency systems.
“LCRD will demonstrate all of the advantages of using laser systems and allow us to learn how to use them best operationally,” said Principal Investigator David Israel at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, in a release. “With this capability further proven, we can start to implement laser communications on more missions, making it a standardised way to send and receive data.”
LCRD has two optical terminals – one to receive data from a user spacecraft, and the other to transmit data to ground stations. The modems will translate the digital data into laser signals. This will then be transmitted via encoded beams of light. These capabilities make LCRD NASA’s first two-way, end-to-end optical relay, the agency said in a release.
Laser VS radio
Laser communications and radio waves use different wavelengths of light. Laser uses infrared light and has a shorter wavelength than radio waves. This will help the transmission of more data in a short time. According to a release from NASA: “It would take roughly nine weeks to transmit a completed map of Mars back to Earth with current radio frequency systems. With lasers, we can accelerate that to about nine days.”
Using infrared lasers, LCRD will send data to Earth at 1.2 gigabits-per-second (Gbps). At this speed, it will take less than a minute to download a movie.
Other advantages
Optical communications systems are smaller in size, weight, and require less power compared with radio instruments. “A smaller size means more room for science instruments. Less weight means a less expensive launch. Less power means less drain on the spacecraft’s batteries. With optical communications supplementing radio, missions will have unparalleled communications capabilities,” the agency says.
Where will the laser system be?
The LCRD payload is hosted onboard the US Department of Defense’s Space Test Program Satellite 6 (STPSat-6). It will be in a geosynchronous orbit, over 35,000km above Earth.
For the first two years, LCRD will test its communications capabilities. It will be controlled by engineers at the LCRD mission’s ground stations in California and Hawaii. The team will send test data through radio frequency signals and the LCRD will reply using optical signals.
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The Atlas V with the STP Sat-6 spacecraft carrying NASA's LCRD mission. (Twitter/@nasahqphoto) 
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