Japan launches advanced communications test satellite
BY STEPHEN CLARK
Posted: December 18, 2006
Japan's largest satellite was launched by the nation's most powerful rocket Monday to begin a mission testing technologies to aid the burgeoning mobile communications industry.
Liftoff of Japan's eighth Engineering Test Satellite occurred at 0632 GMT (1:32 a.m. EST) from the Yoshinobu launch complex at the Tanegashima space center. After rising vertically away from its launch pad on the southern tip of the Japanese island chain, the 174-foot tall H-2A rocket performed pitch and roll maneuvers to set an easterly course over the Pacific Ocean.
The 12,787-pound satellite separated from the launcher's second stage 27 minutes later, followed by detection of the first signals from the spacecraft and confirmation the solar panels had unfurled. Officials with the Japan Aerospace Exploration Agency declared the flight a success.
The H-2A rocket used Monday featured four large 49-foot long solid rocket boosters, marking it the most powerful rocket in the history of Japan's space program. Previous H-2A launchers had just two large boosters and a collection of smaller solid-fueled motors.
The extra boosters allow the rocket to deliver up to 2,500 additional pounds to geostationary transfer orbit, according to a JAXA fact sheet.
Next for ETS 8 will be a series of adjust burns to gradually circularize its orbit around Earth and reduce its inclination. The craft will be permanently located in geostationary orbit 22,300 miles over the Equator at 146 degrees East longitude, where it will match the Earth's rotation and appear to hover directly above the Pacific Ocean near New Guinea.
Also called Kiku 8, the spacecraft carries a pair of solar array wings and two large reflector antennas, which will both span more than 130 feet tip-to-tip when deployments are complete. Each antenna has dimensions of about 62 feet by 56 feet, or about the area of a tennis court, according to JAXA.
The mesh reflectors were the focus of much scrutiny during the development of ETS 8. JAXA engineers conducted two test missions to deploy replicas of the antenna in space before proceeding with final preparations for the launch.
Each antenna contains 14 hexagonal modules. Engineers plan to use one for transmitting signals and the other as a receiver.
From its post in space, ETS 8's large antennas will have enough power to reach small portable user terminals across Japan. An on-board S-band communications system will facilitate the experiments.
ETS 8 will be able to directly communicate with hand-held devices modeled after cell phones and computers. JAXA developed two units specifically for use in tests with ETS 8 - a tiny phone-like unit and a portable device similar to a laptop computer.
Another Japanese government agency spearheaded the development of a mobile unit capable of voice communications through ETS 8. The device is smaller than many earlier models of satellite phones due to the intensity of signals sent through the craft's large antennas, according to JAXA.
ETS 8 can also reach users in remote areas not served by terrestrial networks.
"It is extremely important for Japanese people to stabilize the communication infrastructure to transmit accurate information not only for our daily lives but in terms of disaster preparation and social security," said Akio Tsujibata, ETS 8 project manager.
Scheduled to last up to 10 years, the mission includes a number of other technologies, including an on-board clock that will transmit signals used to generate time and position estimates on the ground.
The experiment will test the feasibility of using geostationary satellites as positioning satellites. Signals from the U.S. Global Positioning System will also be incorporated in the tests.
JAXA officials hope lessons learned from the ETS 8 mission can be used in designing future communications satellites.
The next launch of the H-2A rocket is scheduled for early next year with two Japanese government spy satellites. The nation's second radar reconnaissance satellite and third optical observation craft will fly into orbit together before April, according to JAXA.
The flight will be the fourth devoted to launching Japanese spy satellites. Two earlier missions were successful and another ended in failure.
The most recent launch of a classified Japanese payload was in September, when an optical reconnaissance satellite was put in space. A radar craft was removed from that flight earlier this year.