Broadband Internet satellite launched by Japan
BY STEPHEN CLARK
Posted: February 23, 2008
A cutting edge Japanese satellite was hurled into orbit Saturday, beginning a mission to plant the seeds for a space-based infrastructure to spread access to information in remote corners of the Far East and Southeast Asia.
Built to help bring broadband Internet services into underserved households and businesses, the Wideband Internetworking engineering test and Demonstration Satellite will reach both local markets in Japan and international centers across the Asia-Pacific region.
"The purpose of WINDS is to develop and demonstrate technology to establish the world's most advanced information society," said Yasuo Nakamura, the mission's project manager.
The craft was driven into space atop an H-2A rocket launched from the Yoshinobu complex on Tanegashima Island at the southern end of the Japanese archipelago. The orange and white launcher, fitted with two large solid rocket boosters and four smaller strap-on motors, bolted into the sky at 0855 GMT (3:55 a.m. EST) Saturday.
Liftoff slipped to the end of the day's window because of a boat in a downrange restricted zone and persistent high winds that reached nearly 40 miles per hour. The gusts finally died down enough for engineers to clear the rocket for flight shortly after sunset.
The rocket arced eastward from Tanegashima, shedding its boosters and nose cone before its first stage exhausted its supply of cryogenic propellant about six-and-a-half minutes after liftoff. The H-2A's second stage fired twice to inject the WINDS payload into its targeted orbit, and live video from the rocket showed spacecraft separation at the 28-minute mark in the mission.
Nicknamed Kizuna, the 10,692-pound satellite was expected to be released in an orbit with a high point of 22,354 miles and a low point of 155 miles. The geosynchronous transfer orbit should have an inclination of 28.5 degrees, according to prelaunch estimates.
Japan Aerospace Exploration Agency officials declared the launch a success after acquiring communications signals from Kizuna.
The flight was delayed from Feb. 15 to give technicians time to resolve a problem with an attitude control thruster on the rocket's second stage. Officials ordered the replacement of a faulty part before pressing ahead with final preparations.
Kizuna will use its own propulsion module to gradually boost its orbit to an altitude of approximately 22,300 miles and reduce its inclination to zero degrees to enter geosynchronous orbit, where the craft's velocity will match the speed of Earth's rotation. Kizuna will be permanently parked above the equator at 143 degrees east longitude, or above the Pacific Ocean north of New Guinea.
Built by Mitsubishi Heavy Industries Ltd., the satellite will deploy its antennas and complete four months of systems testing before its demonstrations begin in July.
The $484 million five-year mission is the first step in a government-led demonstration of technologies that could revolutionize Internet-based communications. JAXA is fronting most of the mission's funding, with the National Institute of Information and Communications Technology providing the remaining $56 million, according to a JAXA spokesperson.
The name Kizuna, which means "ties between people," was selected from suggestions submitted by the public.
Kizuna features two 7.9-foot Ka-band dish reflectors attached to a multi-beam antenna designed to serve locales across Asia. One dish will focus on nine regions in Japan, plus parts of Korea, Beijing and Shanghai. Another reflector will reach a broader swath of the Asia-Pacific.
Enhanced with a powerful amplifier, the multi-beam antenna enables ultra-high-speed two-way communications with data rates near 1.2 gigabytes per second for businesses with ground antennas more than 15 feet in diameter. Four-foot ground antennas can reach two-way communication speeds of 155 megabytes per second, according to JAXA.
Individuals with 1.5-foot antennas can also receive a sizable boost in communications speeds through Kizuna. Those dishes will be able to receive information at a rate of 155 megabytes per second, faster than commercial fiber-optic networks.
JAXA officials say such high-speed communications are difficult to achieve through conventional satellites and small ground terminals. A cornerstone of Kizuna's mission is to allow smaller dishes to attain communication rates previously reserved for large and expensive ground antennas.
Ka-band frequencies are typically hindered by rain, but Kizuna's multi-beam antenna can allocate its power capacity to regions based on both weather conditions and real-time demand. This provides a level of flexibility unmatched by most current communications satellites, JAXA officials said.
"It will allocate power efficiently by sending a stronger signal to a rainy region, and a weaker signal to a sunny region," Nakamura said.
Kizuna also carries a Ka-band phased array antenna with an arrangement of transmitters and receivers capable of rapidly changing coverage zones to respond to demand.
The phased array antenna will reach an area stretching from the central Pacific to India, opening up one-third of the planet to Kizuna's communications experiments.
A switchboard-like device aboard Kizuna can instantly route uplinked messages to their intended destinations, a notable departure from most communications satellites that require help from the ground.
Kizuna will begin technology experiments in July with extensive testing of its communications payload to assess its ability to support subsequent demonstrations. By October, engineers expect to kick off a series of advanced experiments.
Controllers will attempt to beam broadband Internet into homes in remote parts of Asia through simple and inexpensive ground antennas to help bridge the digital divide between urban and rural citizens.
"Although the Internet is very popular in urban areas, connectivity is not yet sufficient in many mountainous regions, on remote islands, or in Asian countries where the communications infrastructure is not well developed," Nakamura said. "(Kizuna) can make advanced high-speed communications available even in such areas."
Officials will also test the viability of the system for use in disasters that may dissolve terrestrial networks. Kizuna's antennas will link up with small mobile stations and demonstrate replacing a severed backbone Internet line to prove a satellite-based communications system can step in if tragedy strikes.
"Even if communication networks are disrupted and electricity lines are down, an Internet connection can be easily set up anywhere," Nakamura said.
Kizuna will also demonstrate multicasting between teachers and students in a distance learning program. Multicasting using Kizuna will facilitate more interactive communications among remote classes, according to Nakamura.
Kizuna will conduct 53 other experiments selected from private proposals for the remainder of its mission.
"We'd like to explore the entire potential of (Kizuna) as we ensure the success of all these experiments," Nakamura said.
The next flight of the H-2A rocket will launch GOSAT, a satellite to measure the amount of harmful greenhouse gases in Earth's atmosphere. That mission is scheduled for launch this fall.
INDEX | PLUS | NEWS ARCHIVE | LAUNCH SCHEDULE
ASTRONOMY NOW | STORE
© 2014 Spaceflight Now Inc.