Japanese data relay satellite launched on H-2A rocket – Spaceflight Now


editor’s Note: Updated at 5 pm EST (1000 GMT) after confirmation of a successful launch.

A Japanese H-2A rocket launched from the Tanegashima Space Center on Sunday. Sincerely: MHI

A Japanese satellite designed to relay data and imagery from civilian and military Earth observation spacecraft boarded an H-2A rocket on Sunday.

The dual-use communications satellite boarded the H-2A rocket in orbit from Tanegashima Space Center in southern Japan at 2:25 EST (0725 GM-4; 4:25 PM Japan Standard Time).

A live video feed from a media audience in Tanegashima showed a 174-foot-long (53-meter) H-2A rocket flying in broken clouds above the spaceport.

The Japan Aerospace Exploration Agency did not provide a live webcast on Sunday, due to the possibility of a sensitive military relationship with the data relay payload. Japanese authorities have also not disclosed the exact operational status of the new satellite in geostationary orbit, or specifics on its mass and size.

Powered by a hydrogen-fueled LE-7A main engine and two strap-on solid rocket boosters, the H-2A launcher climbed into the stratosphere with a thrust of 1.4 million pounds as the rocket moved east over Tanegashima over the Pacific Ocean .

Burned two strap-on boosters and lifted from the H-2A launcher in less than two minutes.

The H-2A’s main engine shut down and the first stage took off about six and a half minutes into the mission, leaving the cryogenic upper stage firing to keep the data relay satellite in its target egg-shaped transfer orbit. Can go

According to Mitsubishi Heavy Industries, the manufacturer and launch operator of the H-2A rocket, the rocket’s upper stage successfully deployed a data relay satellite into orbit.

Sunday’s launch was the H-2A rocket’s 43rd flight since 2001, and Japan’s fourth space launch of the year.

The H-2A rocket was expected to drop its payload – part of the Japan data relay system, or JDRS – into elliptical geo-transfer transfer orbit. The satellite will use its own propulsion system to reach a circular geostationary orbit more than 22,000 miles (about 36,000 kilometers) above the equator, where it will enter service and embark on a 10-year mission.

At that height, the satellite will orbit the Earth at a similar rate of rotation, giving it a continuous view over the Asia-Pacific region.

The new satellite carries the Laser Utilization Communication System, or Lucas, developed by the Japan Aerospace Exploration Agency. From its perch in geostationary orbit, the optical communication payload will connect to satellites flying with a near-infrared laser beam several hundred miles above Earth, allowing transmission of data at high rates.

Artist concept of optical data relay satellite of Japan. Sincerely: JAXA

A single data relay satellite can communicate with the user spacecraft for about 40 minutes in each orbit, imagery, scientific data, and other information between the Earth observation satellite and a ground station. The connection spec allows analysts to receive data more quickly if they waited for the observation satellite to pass over an antenna on the ground.

The new optical data relay satellite replaces the Kodama spacecraft of Jaxa, which had S-band and K-band inter-satellite links providing communication speeds of approximately 240 megabits per second. JAXA deactivated the Kodama satellite in 2017 after a 15-year mission.

The laser-equipped relay satellite will allow data transmission at 1.8 gigabits per second, more than seven times faster than the speed possible with Koda. The antenna’s diameter for broadcasting Kodama’s radio frequency was 11.8 feet or 3.6 meters, while the diameter of the laser terminal for an optical relay satellite is 5.5 inches, or 14 centimeters.

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

“Using this as a foothold, LUCAS was developed to achieve significant reliability, miniaturization and significant improvement in communication capability for practical use,” said JAXA.

Built for a 10-year mission, the new optical data relay satellite will operate on Earth observation satellites operated by Japanese civilians and spy and other strategic points on Japan’s fleet intelligence-monitored surveillance spacecraft North Korea.

Civil satellites in development to use the new laser data relay station include Japan’s ALOS 3 and ALOS 4 land imaging observatory. After launch, ALOS 3 and ALOS 4 will collect imagery to assist in disaster response, environmental monitoring, agricultural and forestry management, and urban infrastructure planning.

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