Context: Recently, NASA has launched its new Laser Communications Relay Demonstration(LCRD) which help them to get space-to-ground laser communications.

About LCRD

• It involves laser communications that are also called optical communications which uses infrared light to send information.

Orbit: 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 35,000 km above Earth.

• It 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.

Purpose: It has been launched to help demonstrate the benefits of space-to-ground laser communications also called optical communications.

• Location of the Laser Systems: Unlike radio frequency communications, optical signals cannot penetrate cloud coverage. That’s why, LCRD will transmit data to two ground stations, located in California and Hawaii. These locations were chosen for their minimal cloud coverage.  

Benefits offered by LCRD

• 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 help the agency test optical communication in space.

Laser vs Radio

• Laser communications and radio waves use different wavelengths of light. It uses infrared light and has a shorter wavelength than radio waves.
• This will help the transmission of more data in a short time.
• Using infrared lasers, LCRD will send data to Earth at 1.2 gigabits-per-second (Gbps).
• 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, says NASA.

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.