Japanese data relay satellite set to launch on H-2A rocket

A Japanese satellite designed to relay data and images from a civilian and military Earth observation spacecraft is expected to take off on Sunday aboard an H-2A rocket.

According to Mitsubishi Heavy Industries, the dual-use communications satellite is expected to launch an H-2A rocket into orbit at 2:25 a.m. EST (7:25 a.m. GMT; 4:25 p.m. Japan Standard Time) from the Tanegashima Space Center in the south. of Japan, the builder and launch operator of the H-2A rocket.

The H-2A rocket will deploy the spacecraft – which is part of the Japanese Data Relay System, or JDRS – into an elliptical geostationary transfer orbit about half an hour after takeoff. The satellite will use its own propulsion system to reach a circular geostationary orbit more than 22,000 miles (nearly 36,000 kilometers) above the equator, where it will enter service and begin a 10-year mission.

At this altitude, the satellite will orbit at the same speed of Earth’s rotation, giving it a continuous view of the Asia-Pacific region.

The new satellite carries the payload of the laser-based communications system, or LUCAS, developed by the Japan Aerospace Exploration Agency. From its perch in geostationary orbit, the optical communications payload will connect with satellites flying several hundred kilometers above the Earth with a near infrared laser beam, allowing data transmission at high data rates.

A single data relay satellite can communicate with a user spacecraft for approximately 40 minutes in each orbit, relaying images, scientific data, and other information between the Earth observation satellite and a ground station. The connection allows imagery analysts to receive data faster than if they waited for the observation satellite to pass over a ground antenna.

The new optical data relay satellite replaces JAXA’s Kodama spacecraft, which had both S-band and Ka-band inter-satellite links offering communication speeds of around 240 megabits per second. JAXA decommissioned the Kodama satellite in 2017 after a 15-year mission.

The laser-equipped relay satellite will enable data transmission speeds of up to 1.8 gigabits per second, more than seven times faster than speeds possible with Kodama. Kodama’s radio-frequency transmissions antenna was 11.8 feet, or 3.6 meters in diameter, while the optical relay satellite’s laser terminal was 5.5 inches, or 14 centimeters in diameter.

JAXA launched an experimental test satellite named Kirari in 2005 to demonstrate inter-satellite laser communication links.

“Using this as an anchor point, LUCAS has been developed to achieve high reliability, miniaturization and a significant improvement in communication capability for practical use,” JAXA said.

Designed for a 10-year mission, the new optical data relay satellite will serve Japanese civilian-operated Earth observation satellites and surveillance spacecraft from the Japanese intelligence-gathering fleet spying on North Korea and other strategic points of interest.

JAXA is not expected to provide a live webcast of the Sunday launch, possibly due to the sensitive military connection with the data relay payload. Japanese officials have also not disclosed the exact operating position of the new satellite in geostationary orbit, nor specifications for its mass and size.

Civilian satellites in development that are ready to use the new laser data relay station include the ALOS 3 and ALOS 4 terrestrial imaging observatories from Japan. Once launched, ALOS 3 and ALOS 4 will collect imagery to help with disaster response, environmental monitoring, agriculture and forestry management, and urban infrastructure planning.

Sunday’s launch will mark the 43rd flight of an H-2A rocket since 2001, and the fourth Japanese space launch of the year.

Powered by a hydrogen-powered LE-7A main engine and two strap-on solid rocket thrusters, the H-2A launcher will pull away from the Tanegashima space center with 1.4 million pounds of thrust and head towards the is over the Pacific Ocean.

The two strap-on boosters will burn and drop the 174-foot-high (53-meter) rocket within two minutes of take-off. The main engine of the H-2A will shut down and the first stage will separate approximately six and a half minutes from the mission, leaving the cryogenic upper stage to perform a pair of shots to place the data relay satellite in its targeted egg. shaped transfer orbit.

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